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  • Product Name:Methylene, oxo-

  • CAS Number: 201230-82-2


  • Molecular Weight:28.0104

  • Molecular Formula: CO

  • HS Code:

  • Mol File:201230-82-2.mol


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  • Signal Word:no data available

  • Hazard Statement:no data available

  • First-aid measures: General adviceConsult a physician. Show this safety data sheet to the doctor in attendance.If inhaled If breathed in, move person into fresh air. If not breathing, give artificial respiration. Consult a physician. In case of skin contact Wash off with soap and plenty of water. Consult a physician. In case of eye contact Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician. If swallowed Never give anything by mouth to an unconscious person. Rinse mouth with water. Consult a physician.

  • Fire-fighting measures: Suitable extinguishing media Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide. Wear self-contained breathing apparatus for firefighting if necessary.

  • Accidental release measures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. For personal protection see section 8. Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided. Pick up and arrange disposal. Sweep up and shovel. Keep in suitable, closed containers for disposal.

  • Handling and storage: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Avoid exposure - obtain special instructions before use.Provide appropriate exhaust ventilation at places where dust is formed. For precautions see section 2.2. Store in cool place. Keep container tightly closed in a dry and well-ventilated place.

  • Exposure controls/personal protection:Occupational Exposure limit valuesBiological limit values Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday. Eye/face protection Safety glasses with side-shields conforming to EN166. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU). Skin protection Wear impervious clothing. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace. Handle with gloves. Gloves must be inspected prior to use. Use proper glove removal technique(without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands. The selected protective gloves have to satisfy the specifications of EU Directive 89/686/EEC and the standard EN 374 derived from it. Respiratory protection Wear dust mask when handling large quantities. Thermal hazards

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Relevant articles and documentsAll total 2075 Articles be found

A Ru(II)-Mn(I) Supramolecular Photocatalyst for CO2 Reduction

Fabry, David C.,Koizumi, Hiroki,Ghosh, Debashis,Yamazaki, Yasuomi,Takeda, Hiroyuki,Tamaki, Yusuke,Ishitani, Osamu

, p. 1511 - 1518 (2020)

Supramolecular photocatalysts for CO2 reduction, constituted of redox photosensitizer, catalyst, and bridging ligand, play crucial roles in constructing hybrid systems with solid materials and photoelectrochemical cells for artificial photosynthesis. We report the first supramolecular photocatalysts with a Mn(I) catalyst [MnBr(CO)3(BL)] and photosensitizer unit(s) [Ru(dmb)2(BL)]2+ (dmb = 4,4′-dimethyl-2,2′-bipyridine, BL = bridging ligand). A 1:1 ratio between the redox photosensitizer and catalyst units showed higher activity for HCOOH formation in comparison to the corresponding mixed system of mononuclear complexes.

Atmospheric sink of methyl chlorodifluoroacetate and ethyl chlorodifluoroacetate: Temperature dependent rate coefficients, product distribution of their reactions with Cl atoms and CF2ClC(O)OH formation

Blanco, María B.,Barnes, Ian,Wiesen, Peter,Teruel, Mariano A.

, p. 51834 - 51844 (2016)

Rate coefficients as a function of temperature have been measured for the first time for the gas-phase reactions of chlorine atoms with methyl chlorodifluoracetate (k1) and ethyl chlorodifluoroacetate (k2) using the relative rate technique. The experiments were carried out in a 1080 L photoreactor over the temperature range 287-313 K at a total pressure of 1000 ± 10 mbar of synthetic air using in situ FTIR spectroscopy to monitor reactants and products. The following Arrhenius expressions were obtained: k(MCDFA+Cl) = (9.6 ± 5.1) × 10-12exp[-(1363 ± 79)/T] and k(ECDFA+Cl) = (64.4 ± 29.7) × 10-12exp[-(1110 ± 68)/T]. The kinetic results are compared with previous experimental and theoretical studies. In addition, a product study of the reactions of Cl with methyl chlorodifluoracetate and ethyl chlorodifluoroacetate is reported. The results indicate that in the absence of NOx the main fate of the alkoxy radicals formed after H-atom abstraction by Cl from the -CH3 group in methyl chlorodifluoroacetate is reaction of the radical with O2 to form the mixed anhydride CF2ClC(O)OC(O)H. In the case of ethyl chlorodifluoroacetate the main fate of the alkoxy formed via H-atom abstraction by Cl from the -CH2- entity in the ethyl group is α-ester rearrangement to produce chlorodifluoroacetic acid and the corresponding radical. The yields of chlorofluoracetic acid (CF2ClC(O)OH) obtained were as follows: (34 ± 5)% and (86 ± 8)% for the reactions of Cl with CF2ClC(O)OCH3 and CF2ClC(O)OCH2CH3, respectively. The measured yields are rationalized in terms of mechanisms consisting of competitive reaction channels for the formed products in the oxidation, i.e. reaction with O2, α-ester rearrangement and a decomposition pathway. Atmospheric implications are discussed according to the rate coefficients obtained as a function of temperature and altitude, and regarding the formation of chlorofluorocarboxylic acid.

Investigation of the thermal decomposition of ketene and of the reaction CH2 + H2 ? CH3 + H

Friedrichs, Gernot,Wagner, Heinz Gg.

, p. 1601 - 1623 (2001)

Using frequency modulation (FM) spectroscopy singlet methylene radicals have been detected for the first time behind shock waves. The thermal decomposition of ketene served as source for metylene radicals at temperatures from 1905 to 2780 K and pressures around 450 mbar. For the unimolecular decomposition reaction, (1) CH2CO+M → CH2 +CO+M, the rate constants obtained are: k1 = (9.5±5.7) · 1015 · exp[(-244±25) kJ mol-1/RT] cm3mol-1 s-1. As a first study of a methylene reaction at high temperatures by diretly tracing methylene the reaction of methylene with hydrogen, (8+9) 1.3CH2 + H2 → CH3 + H, was investigated at temperatures from 1930 to 2455 K and pressures around 500 mbar. For the total rate constant of the singlet and triplet methylene reaction a temperature independent value was obtained: log(kg+9/(cm3mol-1s-1)) = 13.89±0.26. A comparison with low temperature literature data and the systematics of activation energies of triplet methylene reactions allowed a consistent description of singlet and triplet contributions and of the forward and reverse reaction. by Oldenbourg Wissenschaftsverlag, Muenchen.

Phenyl-grafted carbon nitride semiconductor for photocatalytic CO2-reduction and rapid degradation of organic dyes

Vidyasagar, Devthade,Manwar, Nilesh,Gupta, Akanksha,Ghugal, Sachin G.,Umare, Suresh S.,Boukherroub, Rabah

, p. 822 - 832 (2019)

Molecular engineering of graphitic carbon nitride (g-C3N4) is achieved by the copolymerization of π-conjugated phenyl urea, melamine, and urea. Integration of aromatic phenyl rings into the heptazine network of g-C3N4 alters its structural, optical and electronic properties. The fusion of the polymeric g-C3N4 core with aromatic phenyl groups induces band gap tuning, which greatly improves the separation and lifetime of charge-carriers. As a result, CO2 photoreduction experiments conducted by using phenyl-grafted g-C3N4 afford methane and formic acid in high yields. Furthermore, a selective model organic pollutant rhodamine B dye is rapidly decomposed under visible-light irradiation. This work suggests that pyrolysis of a suitable aromatic π-deficient molecular dopant such as phenyl urea can drastically alter the photo-response of the carbon nitride photocatalyst and may enhance its photocatalytic activity. Hence, the present work is expected to be of significant value in sustainable energy production and environmental remediation.

Photoactivity of mono- and dicarbonyl complexes of ruthenium(II) bearing an N,N,S-donor ligand: Role of ancillary ligands on the capacity of CO photorelease

Gonzalez, Margarita A.,Carrington, Samantha J.,Chakraborty, Indranil,Olmstead, Marilyn M.,Mascharak, Pradip K.

, p. 11320 - 11331 (2013)

One monocarbonyl and one dicarbonyl complex of ruthenium(II), namely, [Ru(Cl)(CO)(qmtpm)(PPh3)]BF4 (2) and [Ru(Cl)(CO) 2(qmtpm)]ClO4 (3), derived from the tridentate ligand 2-quinoline-N-(2′-methylthiophenyl)methyleneimine (qmtpm) have been synthesized and structurally characterized. The qmtpm ligand binds in a meridional fashion in these carbonyl complexes, and in 3, the two carbon monoxide (CO) ligands are cis to each other. Solutions of 2 in ethanol, chloroform, or acetonitrile rapidly release CO upon illumination with low-power (3-15 mW) light in the 300-450 nm range. Loss of CO from 2 brings about a dramatic color change from yellow to magenta because of the formation of [Ru(Cl)(MeCN)(qmtpm)(PPh3)]BF4 (4). In acetonitrile, photorelease of CO from 3 under 360 nm light occurs in two steps, and the violet photoproduct [Ru(Cl)(MeCN)2(qmtpm)]+ upon reaction with Ag+ and PPh3 affords red [Ru(MeCN)2(qmtpm) (PPh3)](ClO4)2 (5). The structure of 5 has also been determined by X-ray crystallography. Reduced myoglobin assay confirms that 2 and 3 act as photoactive CO-releasing molecules (photoCORMs) that deliver 1 and 2 equiv of CO, respectively. The results of density functional theory (DFT) and time-dependent DFT studies confirm that electronic transitions from molecular orbitals with predominantly Ru-CO character to ligand-based π* orbitals facilitate CO release from these two photoCORMs. Complexes 2-5 have provided an additional opportunity to analyze the roles of the ancillary ligands, namely, PPh3, Cl-, and MeCN, in shifting the positions of the metal-to-ligand charge-transfer bands and the associated sensitivity of the two photoCORMs to different wavelengths of light. Collectively, the results provide helpful hints toward the future design of photoCORMs that release CO upon exposure to visible light.

The p-Orbital Delocalization of Main-Group Metals to Boost CO2 Electroreduction

He, Sisi,Ni, Fenglou,Ji, Yujin,Wang, Lie,Wen, Yunzhou,Bai, Haipeng,Liu, Gejun,Zhang, Ye,Li, Youyong,Zhang, Bo,Peng, Huisheng

, p. 16114 - 16119 (2018)

Enhancing the p-orbital delocalization of a Bi catalyst (termed as POD-Bi) via layer coupling of the short inter-layer Bi?Bi bond facilitates the adsorption of intermediate *OCHO of CO2 and thus boosts the CO2 reduction reaction (CO2RR) rate to formate. X-ray absorption fine spectroscopy shows that the POD-Bi catalyst has a shortened inter-layer bond after the catalysts are electrochemically reduced in situ from original BiOCl nanosheets. The catalyst on a glassy carbon electrode exhibits a record current density of 57 mA cm?2 (twice the state-of-the-art catalyst) at ?1.16 V vs. RHE with an excellent formate Faradic efficiency (FE) of 95 %. The catalyst has a record half-cell formate power conversion efficiency of 79 % at a current density of 100 mA cm?2 with 93 % formate FE when applied in a flow-cell system. The highest rate of the CO2RR production reported (391 mg h?1 cm2) was achieved at a current density of 500 mA cm?2 with formate FE of 91 % at high CO2 pressure.

CO2 hydrogenation to methanol on Ga2O3-Pd/SiO2 catalysts: Dual oxide-metal sites or (bi)metallic surface sites?

Collins, Sebastián E.,Baltanás, Miguel A.,Delgado, Juan José,Borgna, Armando,Bonivardi, Adrian L.

, p. 154 - 162 (2021)

A series of palladium (2 wt.%) catalysts supported on silica (301 m2/g) and loaded with increasing amount of gallium – ratio of Ga/Pd = 2, 4 and 8 atom/atom – were investigated for CO2 hydrogenation to methanol. The turnover frequency to methanol (H2/CO2 = 3; 523 K, 3 MPa), based on surface palladium, showed a 200-fold enhancement as compared to the monometallic Pd/SiO2 catalyst. Additionally, the apparent activation energy for methanol synthesis decreased from 60 kJ/mol on Pd/SiO2 to ~40 kJ/mol on the supported Ga-Pd catalysts. Characterization of the Pd-Ga catalyst series by X-ray absorption spectroscopy and high resolution transmission electron microscopy indicates the formation of Pd2Ga bimetallic nanoparticles partially covered by a thin layer of Ga2O3 on the silica surface. In situ infrared spectroscopy was employed to examine the reaction mechanism during the CO2 adsorption and hydrogenation at 0.7 MPa. It is proposed a bifunctional pathway where the carbonaceous species bound to the gallium oxide surface are hydrogenated, stepwise, to formate and methoxy groups by atomic hydrogen, which spillovers from the Pd-Ga bimetallic nanoparticles.

Dynamic Changes in the Structure, Chemical State and Catalytic Selectivity of Cu Nanocubes during CO2 Electroreduction: Size and Support Effects

Grosse, Philipp,Gao, Dunfeng,Scholten, Fabian,Sinev, Ilya,Mistry, Hemma,Roldan Cuenya, Beatriz

, (2018)

In situ and operando spectroscopic and microscopic methods were used to gain insight into the correlation between the structure, chemical state, and reactivity of size- and shape-controlled ligand-free Cu nanocubes during CO2 electroreduction (

Click and Release: A Chemical Strategy toward Developing Gasotransmitter Prodrugs by Using an Intramolecular Diels–Alder Reaction

Ji, Xingyue,Zhou, Cheng,Ji, Kaili,Aghoghovbia, Robert E.,Pan, Zhixiang,Chittavong, Vayou,Ke, Bowen,Wang, Binghe

, p. 15846 - 15851 (2016)

Prodrug strategies have been proven to be a very effective way of addressing delivery problems. Much of the chemistry in prodrug development relies on the ability to mask an appropriate functional group, which can be removed under appropriate conditions. However, developing organic prodrugs of gasotransmitters represent unique challenges. This is especially true with carbon monoxide, which does not have an easy “handle” for bioreversible derivatization. By taking advantage of an intramolecular Diels–Alder reaction, we have developed a prodrug strategy for preparations of organic CO prodrugs that are stable during synthesis and storage, and yet readily release CO with tunable release rates under near physiological conditions. The effectiveness of the CO prodrug system in delivering a sufficient quantity of CO for possible therapeutic applications has been studied using a cell culture anti-inflammatory assay and a colitis animal model. These studies fully demonstrate the proof of concept, and lay a strong foundation for further medicinal chemistry work in developing organic CO prodrugs.

Changing the Product Selectivity for Electrocatalysis of CO2 Reduction Reaction on Plated Cu Electrodes

Li, Hong,Qin, Xianxian,Jiang, Tianwen,Ma, Xian-Yin,Jiang, Kun,Cai, Wen-Bin

, p. 6139 - 6146 (2019)

Electrochemical reduction of carbon dioxide (CO2RR) on various types of Cu electrodes to useful chemicals and fuels has attracted much attention. Herein, we comparatively investigate the distributions of CO2RR products over electroplated Cu, chemically plated boron-doped Cu (Cu?B) and electroplated phosphorus-doped Cu (Cu?P) electrodes. A global Faradaic efficiency of more than 50 % can be reached for the C2+ (ethylene, ethanol and n-propanol) products on both plated Cu?B and Cu?P electrodes at ~?1.15 V vs. RHE in 0.1 M KHCO3 electrolyte. Moreover, in situ surface enhanced infrared spectroscopy results together with quantitative analysis of the CO2RR products reveal a more facile conversion/depletion of the *CO intermediate after B- and P-doping, for which Cu?B promotes the C2+ products while Cu?P enhances both C2+ generation and CH4 evolution at faster *CO consumption. The present work suggests the vital role of *CO in the step of C?C bonding formation and highlights that the metalloid doping may alter the reactivity and selectivity of the intermediate.


Colbourne, David,Westwood, Nicholas P. C.

, p. 2049 - 2054 (1985)

HeI Photoelectron spectra are reported for the mono- and di-chloro-and-bromo-ketenes (XHC=C=O and X2C=C=O, X=Cl,Br) generated in high yield as unstable molecules from thermolysis of acid halides.The spectra are discussed and assigned by reference to the parent ketene molecule, orbital trends, and comparison with theoretical calculations.

High-performance and long-lived Cu/SiO2 nanocatalyst for CO2 hydrogenation

Wang, Zhi-Qiao,Xu, Zhong-Ning,Peng, Si-Yan,Zhang, Ming-Jian,Lu, Gang,Chen, Qing-Song,Chen, Yumin,Guo, Guo-Cong

, p. 4255 - 4259 (2015)

Cu-based nanocatalysts have been widely used for CO2 hydrogenation, but their poor stability is the bottleneck for further industrial applications. A high-performance and long-lived Cu/SiO2 nanocatalyst was synthesized by an ammonia-evaporation method for CO2 hydrogenation. The conversion of CO2 reaches up to 28%, which is close to the equilibrium conversion of CO2 (30%), and the selectivity to methanol is 21.3%, which is much higher than the equilibrium selectivity (6.6%) at 320 °C and 3.0 MPa. Furthermore, after 120 h of evaluation, the conversion can be still maintained at a high value (27%), which is much better than a Cu/SiO2 catalyst prepared by traditional impregnation. The Cu+ species has been demonstrated to be the active component for the activation and conversion of CO2. The higher ratio of Cu+/(Cu0 + Cu+) and interaction between the metal and support deriving from copper phyllosilicate are mainly responsible for the high catalytic activity and excellent stability, respectively.

Morphology Modulation-Engineered Flowerlike In2S3 via Ionothermal Method for Efficient CO2 Electroreduction

Feng, Jiaqi,Gao, Hongshuai,Feng, Jianpeng,Liu, Lei,Zeng, Shaojuan,Dong, Haifeng,Bai, Yinge,Liu, Licheng,Zhang, Xiangping

, p. 926 - 931 (2020)

Electroreduction of carbon dioxide (CO2) to chemicals is a promising route to convert and utilize CO2 under atmospheric conditions. However, the relative poor reaction efficiency seriously hinders the practical applications of this route. In this work, flowerlike In2S3 assembled by nanoflakes was synthesized via ionothermal method and exhibited a high Faradaic efficiency (FE) of 86 % with excellent formate formation rate of 478 μmol h?1 cm?2 in ionic liquid (IL) electrolyte. Flowerlike structure can provide large electrochemically active surface area and enhance mass transfer rate. Additionally, density functional theory (DFT) calculations reveal that the origin of the improved performance can be attributed to the large adsorption energy of CO2 * and OCHO* intermediate on the (440) facet which is the main exposed crystal facet of flowerlike In2S3.[f1].

Low Temperature Oxidative Coupling of Methane by Perovskite Oxide

Li, Xiao-Hong,Fujimoto, Kaoru

, p. 1581 - 1584 (1994)

Perovskite oxides, SrTiO3 which was dopped with MgO and contained oxygen defects, oxidized methane to C2 coupled hydrocarbons at 425 deg C, with the selectivity over 90percent.The used oxides could be regenerated by being treated in air at 425 deg C.Adsorbed oxide ion on the defect seemed to be responsible for their oxidation activity.

Reaction volume and enthalpy changes in photochemical reaction detected by the transient grating method; photodissociation of diphenylcyclopropenone

Terazima, Masahide,Hara, Takashi,Hirota, Noboru

, p. 577 - 582 (1995)

A method for the measurement of reaction volume (ΔV) and enthalpy (ΔH) changes of a photochemical reaction is presented based on the transient grating technique.Since ΔV and ΔV contributions are detected separately by the time-resolved manner, this new me

Diffuse Reflectance Infrared Fourier Transform Spectroscopic Investigation of the Decomposition

Venter, Jeremy J.,Vannice, M. Albert

, p. 4158 - 4167 (1989)

The thermal decomposition of Fe3(CO)12 has been studied for the first time by dispersing this cluster on an oxygen-free carbon surface and monitoring its behavior by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS).The Fe3(CO)12 cluste

Fuel composition and diluent effect on gas transport and performance of anode-supported SOFCs

Jiang, Yi,Virkar, Anil V.

, p. A942-A951 (2003)

Anode-supported solid oxide fuel cells (SOFCs) with Ni+yttria-stabilized zirconia (YSZ) anode, YSZ-samaria-doped ceria (SDC) bilayer electrolyte, and Sr-doped LaCoO3 (LSC)+SDC cathode were fabricated. Fuel used consisted of H2 diluted with He, N2, H2O, or CO2, mixtures of H2 and CO, and mixtures of CO and CO2. Cell performance was measured at 800°C with the above-mentioned fuel gas mixtures and air as oxidant. For a given concentration of the diluent, cell performance was higher with He as the diluent than with N2 as the diluent. Mass transport through porous Ni-YSZ anode for H2-H2O, CO-CO2 binary systems, and H2-H2O-diluent gas ternary systems was analyzed using multicomponent gas diffusion theory. At high concentrations of diluent, the maximum achievable current density was limited by the anodic concentration polarization. From this measured limiting current density, the corresponding effective gas diffusivity was estimated. Highest effective diffusivity was estimated for fuel gas mixtures containing H2-H2O-He mixtures (~0.55 cm2/s), and the lowest for CO-CO2 mixtures (~0.07 cm2/s). The lowest performance was observed with CO-CO2 mixture as a fuel, which in part was attributed to the lowest effective diffusivity of the fuels tested and higher activation polarization.

Novel photocatalytic activity of Cu@V co-doped TiO2/PU for CO2 reduction with H2O vapor to produce solar fuels under visible light

Pham, Thanh-Dong,Lee, Byeong-Kyu

, p. 87 - 95 (2017)

In this study, Cu and V co-doped TiO2 deposited on polyurethane (Cu@V-TiO2/PU) was synthesized as a catalyst for the reduction of CO2 with H2O vapor to preferentially produce CH4 as a valuable solar fuel under visible light. The Cu and V dopants defected into the TiO2 lattice, leading to the formation of Ti3+ and oxygen vacancies in the lattice. The Ti3+ formed in the doped TiO2 lattice created an intermediate band between the valence band and the conduction band of TiO2, leading to an increase in the electron–hole pair separation efficiency of TiO2. The oxygen vacancies existing on the surface of the photocatalyst could induce new adsorption sites to adsorb CO2. The generated electrons and holes reacted with the adsorbed CO2 and with H2O vapor to produce CO and primarily CH4. Therefore, the Cu@V-TiO2/PU photocatalysts successfully utilized visible light as the energy source and H2O vapor as a reductant to reduce CO2 to CO and CH4. The Cu@V-TiO2/PU photocatalysts also supplied sufficient electrons and holes for the selective reduction of CO2 to CH4 rather than CO. The 2Cu@4V-TiO2/PU photocatalyst, with Cu/TiO2 and V/TiO2 ratios of 2 and 4?wt.%, respectively, exhibited the highest photocatalytic activity for CO2 conversion into solar fuels. The production rates of CH4 and CO produced from the CO2 reduction by the 2Cu@4V-TiO2/PU photocatalyst under visible light were 933 and 588?μmol?g?1?cat.?h?1, respectively.

Laser-Induced Activation of Methane at Oxide Surfaces: A Probe of Radical-Surface Interactions

Sayyed, Basseera A.,Stair, Peter C.

, p. 409 - 414 (1990)

C-H bond activation was studied via pulsed laser irradiation of oxides in a methane atmosphere.Carbon monoxide was the major product observed at low power densities and room temperature.Significant amounts of C2 products, ethane, ethylene, and acetylene were formed.CO, C2H6, C2H4, and C2H2 are assigned as primary products of the reaction.Laser-induced methane activation produces *CH3 and :CH2 radical species in the gas phase via a plasma mechanism and is utilized as a tool to study radical-oxide surface interactions.These reactions are surface sensitive as evidenced by the changes in conversion and product selectivity as a function of oxide pretreatment and oxides used.

Effect of Vapor-phase-treatment to CuZnZr Catalyst on the Reaction Behaviors in CO2 Hydrogenation into Methanol

Chen, Shuyao,Zhang, Junfeng,Wang, Peng,Wang, Xiaoxing,Song, Faen,Bai, Yunxing,Zhang, Meng,Wu, Yingquan,Xie, Hongjuan,Tan, Yisheng

, p. 1448 - 1457 (2019)

CuZnZr catalysts prepared by co-precipitation method were treated by vapor-phase-treatment (VPT) method, and used for the synthesis of methanol for CO2 hydrogenation. Compared with conventional co-precipitation method, this VPT with TPABr (TPABr: tetrapropylammonium bromide) induces obvious increases in the particles size of CuO, ZnO and ZrO2, promotes the formation of the rod-like structure, Zn and Zr enrichments on surface and the presence of more concentration of oxygen vacancies. Due to the increases of particle size especially for CuO particles, the activity of the catalyst for CO2 hydrogenation to CO (RWGS reaction) is furthest suppressed, leading to dramatical decrease in conversion of CO2. However, methanol productivity is affected relatively modestly due to the enrichments of Zn and Zr as another active species on the catalyst surface. In addition, catalyst properties and methanol selectivity can be regulated through adjusting the processing time. The catalyst with the processing time of 3 day (CuZnZr-TPABr-3d catalyst) shows a methanol selectivity above 90 % and no obvious deactivation appeared in a period of 100 h reaction.

Sn(101) Derived from Metal-Organic Frameworks for Efficient Electrocatalytic Reduction of CO2

Wu, Jian-Xiang,Zhu, Xiao-Rong,Liang, Ting,Zhang, Xiang-Da,Hou, Shu-Zhen,Xu, Ming,Li, Ya-Fei,Gu, Zhi-Yuan

, p. 9653 - 9659 (2021)

The synthesis of a specific Sn plane as an efficient electrocatalyst for CO2 electrochemical reduction to generate fuels and chemicals is still a huge challenge. Density functional theory (DFT) calculations first reveal that the Sn(101) crystal plane is more advantageous for CO2 electroreduction. A metal-organic framework (MOF) precursor Sn-MOF has been carbonized and then etched to successfully fabricate Sn(101)/SnO2/C composites with good control of the carbonization time and the concentration of hydrochloric acid. The Sn(101) crystal plane of the catalyst could enhance the faradaic efficiency of formate to as high as 93.3% and catalytic stability up to 20 h. The promotion of the selectivity and activity by Sn(101) advances new possibilities for the rational design of high-activity Sn catalysts derived from MOFs.

Room-Temperature Activation of H2 by a Surface Frustrated Lewis Pair

Wang, Lu,Yan, Tingjiang,Song, Rui,Sun, Wei,Dong, Yuchan,Guo, Jiuli,Zhang, Zizhong,Wang, Xuxu,Ozin, Geoffrey A.

, p. 9501 - 9505 (2019)

Surface frustrated Lewis pairs (SFLPs) have been implicated in the gas-phase heterogeneous (photo)catalytic hydrogenation of CO2 to CO and CH3OH by In2O3?x(OH)y. A key step in the reaction pathway is envisioned to be the heterolysis of H2 on a proximal Lewis acid–Lewis base pair, the SFLP, the chemistry of which is described as In???In-OH + H2 → In-OH2+???In-H?. The product of the heterolysis, thought to be a protonated hydroxide Lewis base In-OH2+ and a hydride coordinated Lewis acid In-H?, can react with CO2 to form either CO or CH3OH. While the experimental and theoretical evidence is compelling for heterolysis of H2 on the SFLP, all conclusions derive from indirect proof, and direct observation remains lacking. Unexpectedly, we have discovered rhombohedral In2O3?x(OH)y can enable dissociation of H2 at room temperature, which allows its direct observation by several analytical techniques. The collected analytical results lean towards the heterolysis rather than the homolysis reaction pathway.

Electrocatalytic Reduction of CO2 to Ethylene by Molecular Cu-Complex Immobilized on Graphitized Mesoporous Carbon

Balamurugan, Mani,Choutipalli, Venkata Surya Kumar,Hong, Jung Sug,Im, Sang Won,Jang, Jun Ho,Jeong, Hui-Yun,Kim, Sun Hee,Lee, Kang-Gyu,Lee, Yoon Ho,Nam, Ki Tae,Saravanan, Natarajan,Seo, Hongmin,Subramanian, Venkatesan

, (2020)

The electrochemical reduction of carbon dioxide (CO2) to hydrocarbons is a challenging task because of the issues in controlling the efficiency and selectivity of the products. Among the various transition metals, copper has attracted attention as it yields more reduced and C2 products even while using mononuclear copper center as catalysts. In addition, it is found that reversible formation of copper nanoparticle acts as the real catalytically active site for the conversion of CO2 to reduced products. Here, it is demonstrated that the dinuclear molecular copper complex immobilized over graphitized mesoporous carbon can act as catalysts for the conversion of CO2 to hydrocarbons (methane and ethylene) up to 60%. Interestingly, high selectivity toward C2 product (40% faradaic efficiency) is achieved by a molecular complex based hybrid material from CO2 in 0.1 m KCl. In addition, the role of local pH, porous structure, and carbon support in limiting the mass transport to achieve the highly reduced products is demonstrated. Although the spectroscopic analysis of the catalysts exhibits molecular nature of the complex after 2 h bulk electrolysis, morphological study reveals that the newly generated copper cluster is the real active site during the catalytic reactions.

Catalytic behavior and surface species investigation over γ-Al 2O3 in dimethyl ether hydrolysis

Hirunsit, Pussana,Faungnawakij, Kajornsak,Namuangruk, Supawadee,Luadthong, Chuleeporn

, p. 99 - 105 (2013)

The catalytic behavior and surface species over γ-Al 2O3 in hydrolysis of dimethyl ether (DME) was examined by experimental and theoretical studies. It was experimentally observed that γ-Al2O3 substantially catalyzed DME hydrolysis producing methanol at 250-350 C with high stability at this temperature range with respect to carbon formation. Other carbon-containing species yielded from side reactions were present in trace amounts at temperatures below 375 C. The Density Functional Theory calculations results suggested that DME hydrolysis is thermodynamically favorable on the hydroxylated γ-Al2O 3(1 1 0) but it is not favorable on (1 0 0) surfaces at this reaction temperature range. The DME hydrolysis on γ-Al2O3 is more likely to occur at a hydroxyl surface group which has relatively high acidity.

Carbon Dioxide Hydrogenation over Au/ZrO2 Catalysts from Amorphous Precursors: Catalytic Reaction Mechanism

Koeppel, Rene A.,Baiker, Alfons,Schild, Christoph,Wokaun, Alexander

, p. 2821 - 2828 (1991)

An active catalyst for carbon dioxide hydrogenation is obtained by exposing an amorphous Au25Zr75 alloy to CO2 hydrogenation conditions.During this in situ activation, metallic gold particles of 8.5 nm mean size are formed, and the zirconium component of the catalyst is oxidized to ZrO2.For comparison, a further Au/ZrO2 catalyst was synthesized by coprecipitation, followed by calcination of the amorphous precipitate.The calcination step strongly enhances the activity of the catalyst; gold segregation and zirconia crystallization are found to occur in this process.The structural and chemical changes are characterized by gas adsorption, X-ray diffraction and thermal analysis. The main products of CO2 hydrogenation over these catalysts, as identified by gas chromatography, are methanol and CO.To investigate the reaction mechanism, diffuse reflectance FTIR spectroscopy has been used.Observed surface species are correlated with the formation of gas-phase products.Adsorption of CO2-H2 results in rapid formation of formate as the primary surface intermediate; two types of formate species are clearly detected on the coprecipitated catalyst, and are assigned by means of formic acid adsorption experiments.CO formation from CO2 appears to proceed via surface carbonate, in a surface reaction that corresponds to a 'basic variant' of the reverse water-gas-shift reaction.The CO formed in this process is, in turn, the starting point for a series of surface hydrogenation steps that yield ?-bonded formaldehyde, surface-bound methylate and finally methanol.This sequence of reactions is confirmed by separate CO-H2 adsorption experiments.

Stranks, D. R.

, p. 499 - 504 (1955)

Poe, Anthony,Sekhar, Vasu C.

, p. 5034 - 5035 (1984)

Matrix photochemistry of the complexes (CO)5M = C(OMe)Ph (M = Cr, W) having close-lying reactive MLCT and LF states

Servaas, Peter C.,Stufkens, Derk J.,Oskam, Ad

, p. 61 - 71 (1990)

This article describes the photochemistry of (CO)5M=C(OMe)Ph (M = Cr, W) in inert gas matrices as 10 K at different irradiation wavelengths.The reactions were studied by following the IR spectral changes in the carbonyl and carbene stretching region.Irradiation with visible light into the low-energy MLCT band resulted in complete conversion of the complexes from anti- into syn-configurations.A similar isomerization reaction occurred as the primary photoprocess upon irradiation into the LF band at ca. 350 nm but this reaction was followed by release of CO as a secondary photoprocess, and in the case of the W-complex a subsequent third photochemical reaction was also observed.The photoproduct of this last reaction appeared to be coordinatively saturated, although it still contained a W(CO)4-moiety.In agreement with an earlier proposal based on flash-photolysis data, it is suggested that a C-H bond of the carbene methoxy group interacts with W via a two-electron, three-centre bond, thus occupying the open site at the metal.Conclusions are drawn about the reactivity of the MLCT and LF states of the isomers.

Preparation, characterization and crystal structure of lead(II) tricyanomethanide

Deflon, Victor M.,De Sousa Lopes, Cassia C.,Bessler, Karl E.,Romualdo, Lincoln L.,Niquet, Elke

, p. 33 - 36 (2006)

The so far unknown lead tricyanomethanide, Pb[C(CN)3] 2, was obtained from a saturated aqueous solution of PbCl2 and solid AgC(CN)3. Its IR spectrum and thermal behaviour are described. The crystal structure was determined by single-crystal X-ray diffraction (trigonal, P31m, Z = 3, a = 1414.4(5), c = 409.02(6) pm, R 1 = 0.0249, wR2 = 0.0527). Two crystallographically independent ninefold coordinated Pb atoms are connected by planar tricyanomethanide ions in two distinct bridging coordination modes. The Pb-N distances range between 254 and 293 pm.

Self-Cleaning Catalyst Electrodes for Stabilized CO2 Reduction to Hydrocarbons

Weng, Zhe,Zhang, Xing,Wu, Yueshen,Huo, Shengjuan,Jiang, Jianbing,Liu, Wen,He, Guanjie,Liang, Yongye,Wang, Hailiang

, p. 13135 - 13139 (2017)

A surface-restructuring strategy is presented that involves self-cleaning Cu catalyst electrodes with unprecedented catalytic stability toward CO2 reduction. Under the working conditions, the Pd atoms pre-deposited on Cu surface induce continuous morphological and compositional restructuring of the Cu surface, which constantly refreshes the catalyst surface and thus maintains the catalytic properties for CO2 reduction to hydrocarbons. The Pd-decorated Cu electrode can catalyze CO2 reduction with relatively stable selectivity and current density for up to 16 h, which is one of the best catalytic durability performances among all Cu electrocatalysts for effective CO2 conversion to hydrocarbons. The generality of this approach of utilizing foreign metal atoms to induce surface restructuring toward stabilizing Cu catalyst electrodes against deactivation by carbonaceous species accumulation in CO2 reduction is further demonstrated by replacing Pd with Rh.

The difference of roles of alkaline-earth metal oxides on silica-supported nickel catalysts for CO2 methanation

Guo, Meng,Lu, Gongxuan

, p. 58171 - 58177 (2014)

The roles of alkaline-earth metal oxides on CO2 methanation over modified Ni/SiO2 catalysts were investigated. Ni/MO/SiO2 catalysts with variable elements (M = Mg, Ca, Sr and Ba) were prepared by the sequential impregnatio

1D SnO2 with Wire-in-Tube Architectures for Highly Selective Electrochemical Reduction of CO2 to C1 Products

Fan, Lei,Xia, Zheng,Xu, Meijia,Lu, Yingying,Li, Zhongjian

, (2018)

Electrochemical reduction of CO2 (ERC) into useful products, such as formic acid and carbon monoxide, is a fascinating approach for CO2 fixation as well as energy storage. Sn-based materials are attractive catalysts for highly selective ERC into C1 products (including HCOOH and CO), but still suffer from high overpotential, low current density, and poor stability. Here, One-dimensional (1D) SnO2 with wire-in-tube (WIT) structure is synthesized and shows superior selectivity for C1 products. Using the WIT SnO2 as the ERC catalyst, very high Faradaic efficiency of C1 products (>90%) can be achieved at a wide potential range from ?0.89 to ?1.29?V versus RHE, thus substantially suppressing the hydrogen evolution reaction. The electrocatalyst also exhibits excellent long-term stability. The improved catalytic activity of the WIT SnO2 over the commercial SnO2 nanoparticle indicates that higher surface area and large number of grain boundaries can effectively enhance the ERC activity. Synthesized via a facile and low-cost electrospinning technology, the reduced WIT SnO2 can serve as a promising electrocatalyst for efficient CO2 to C1 products conversion.

Selective Hydrogenation of Carbon Dioxide to Methanol on Cu-ZnO/SiO2 Catalysts Prepared by Alkoxide Method

Okabe, Kiyomi,Sayama, Kazuhiro,Matsubayashi, Nobuyuki,Shimomura, Kin'ya,Arakawa, Hironori

, p. 2520 - 2525 (1992)

Hydrogenation of CO2 to methanol was carried out on Cu-ZnO/SiO2 catalysts at 493 K and 3 MPa with a flow rate of 100 cm3min-1 (H2/CO2=2).Higher selectivity (>90percent) was observed on the catalysts prepared by the alkoxide method than on a conventional catalyst prepared by the impregnation method.The selectivity was higher on the catalysts pretreated with H2 at a higher temperature, except at 873 K.The activity of the catalyst pretreated at 873 K was extremely low, probably because of alloy formation.The results of XRD, XPS, and EXAFS demonstrate that the active species for methanol formation is a large metallic Cu particle covered with a partially oxidized layer interacting with highly dispersed ZnO.

Synthesis of formaldehyde from dimethyl ether on alumina-supported molybdenum oxide catalyst

Peláez, Raquel,Marín, Pablo,Ordó?ez, Salvador

, p. 137 - 145 (2016)

The selective oxidation of DME to formaldehyde over alumina-supported MoOx catalyst (prepared by dry impregnation) is studied in this work. The activity and stability of the catalyst were evaluated in a fixed-bed continuous reactor at different temperatures and reactant concentrations. The influence of the main operating conditions, (DME, O2, CO2 and CO feed concentrations; reaction temperature) on reaction rate and product selectivity was experimentally determined. Thus, DME conversion decreases on increasing DME feed concentration and increases on increasing O2 feed concentration. Formaldehyde selectivity remained almost unaffected. A reaction mechanism, based on a Mars-van-Krevelen redox cycle representing DME oxidation to formaldehyde was used as a basis to develop a kinetic model for the reaction. The resulting simplified model suggests power law dependences for the reaction rate of 0.2 for the O2 and 0.5 for the DME.

Photosensitive iron(II)-based CO-releasing molecules (CORMs) with vicinal amino and diphenylphosphino substituted chelating ligands

Jazzazi, Taghreed M.A.,G?rls, Helmar,Gessner, Guido,Heinemann, Stefan H.,Westerhausen

, p. 63 - 70 (2013)

The reactions of [Fe(H2O)6] [BF4] 2 with aminoethyl-diphenylphosphane and 2-(diphenylphosphino)aniline lead to the formation of trans-[Fe(NC-Me)2(H2NCH 2CH2PPh2)2] [BF4] 2 (1a) and trans-[Fe(NC-Me)2(H2NC 6H4-2-PPh2)2] [BF4] 2 (1b), respectively. One acetonitrile ligand can be substituted by CO yielding [Fe(CO)(NC-Me)(H2NCH2CH2PPh 2)2] [BF4]2 (2a, CORM-P1) and [Fe(CO)(NC-Me)(H2NC6H4-2-PPh2) 2] [BF4]2 (2b, CORM-P2). Upon irradiation with visible light, CO is liberated making especially 2a a promising photo-CORM whereas for 2b a slow and incomplete CO release is observed.

Atmospheric chemistry of CF3CF2CHO: Absorption cross sections in the UV and IR regions, photolysis at 308 nm, and gas-phase reaction with OH radicals (T = 263-358 K)

Antinolo, Maria,Jimenez, Elena,Gonzalez, Sergio,Albaladejo, Jose

, p. 178 - 186 (2014)

The relative importance in the atmosphere of UV photolysis of perfluoropropionaldehyde, CF3CF2CHO, and reaction with hydroxyl (OH) radicals has been investigated in this work. First, the forbidden n → π* transition of the carbonyl chromophore was characterized between 230 and 380 nm as a function of temperature (269-298 K) and UV absorption cross sections, σλ, were determined in those ranges. In addition, IR absorption cross sections were determined between 4000 and 500 cm-1. Pulsed laser photolysis (PLP) of CF3CF 2CHO coupled to Fourier transform infrared (FTIR) was employed to determine the overall photolysis quantum yield, Φλ, at 308 nm and 298 K. Φλ=308 nm was pressure dependent, ranging from (0.94 ± 0.14) at 75 Torr to (0.30 ± 0.01) at 760 Torr. This dependence is characterized by the Stern-Volmer parameters Φλ=308 nm0 = (1.19 ± 0.34) and KSV = (1.22 ± 0.52) × 10-19 cm3 molecule-1. End products of the photodissociation of CF3CF2CHO were measured and quantified by FTIR spectroscopy. Furthermore, the rate coefficients for the OH + CF3CF2CHO reaction, k1, were determined as a function of temperature (T = 263-358 K) by PLP-LIF. At room temperature the rate coefficient is k1(T = 298 K) = (5.57 ± 0.07) × 10 -13 cm3 molecule-1 s-1, whereas the temperature dependence is described by k1(T) = (2.56 ± 0.32) × 10-12 exp{-(458 ± 36)/T} cm3 molecule -1 s-1. On the basis of our results, photolysis of CF 3CF2CHO in the actinic region could be an important removal process for CF3CF2CHO in the atmosphere. The formation of the primary products in the UV photolysis of CF3CF 2CHO is also discussed.

Strong Evidence of the Role of H2O in Affecting Methanol Selectivity from CO2 Hydrogenation over Cu-ZnO-ZrO2

Chen, Jingguang G.,Gao, Wengui,Li, Kongzhai,Na, Wei,Wang, Hua,Wang, Yuhao,Xie, Zhenhua,Zheng, Yane

, p. 419 - 430 (2020)


Novel TiO2/C3N4 Photocatalysts for Photocatalytic Reduction of CO2 and for Photocatalytic Decomposition of N2O

Reli, Martin,Huo, Pengwei,?ihor, Marcel,Ambro?ová, Nela,Troppová, Ivana,Matějová, Lenka,Lang, Jaroslav,Svoboda, Ladislav,Ku?trowski, Piotr,Ritz, Michal,Praus, Petr,Ko?í, Kamila

, p. 8564 - 8573 (2016)

TiO2/g-C3N4 photocatalysts with the ratio of TiO2 to g-C3N4 ranging from 0.3/1 to 2/1 were prepared by simple mechanical mixing of pure g-C3N4 and commercial TiO2

Epoxidation of Ethylene with Products of Thermal Gas-Phase Oxidation of n-Butane

Arsentev, S. D.,Grigoryan, R. R.

, p. 187 - 193 (2020)

Abstract: Epoxidation of ethylene with the reactive products formed during thermal gas-phase oxidation of n-butane has been carried out under flow conditions with the separation of the zones of generation of radicals and their interaction with ethylene. Butane is oxidized in the first section of a two-section reactor, and ethylene is fed to the second section. It has been found that increasing the residence time of a butane–oxygen mixture in the first section of the reactor from 7 to 13 s increases the ethylene oxide accumulation rate. A further increase in the contact time leads to a decrease in the rate. Similarly, increasing the C4H10/O2 ratio in the range of 0.05–0.25 leads to an increase in the rate of accumulation of ethylene oxide. A further increase in this ratio decreases the rate of epoxidation. It has also been found that the temperature dependences of the ethylene oxide accumulation rate in both sections of the reactor pass through a maximum. The obtained data give evidence for the occurrence of the ethylene epoxidation reaction initiated by the n-butane oxidation products under the conditions when ethylene itself is slightly oxidized.

Hydrogenation of CO2to LPG over CuZnZr/MeSAPO-34 catalysts

Du, Ce,Gapu Chizema, Linet,Hondo, Emmerson,Lu, Chengxue,Lu, Peng,Ma, Qingxiang,Mo, Shuting,Tong, Mingliang,Tsubaki, Noritatsu

, p. 9328 - 9336 (2020)

The utilization of CO2to synthesize environmentally benign liquid fuels offers a solution to replacing depleting petroleum resources. Herein, a ternary CuZnZr (CZZ) metal oxide catalyst and a SAPO-34 zeolite were synthesized by co-precipitation and hydrothermal synthesis, respectively. Different metals were impregnated into the latter to obtain MeSAPO-34 (Me = Mn, Zn and Zr). A granule mixture of CZZ and MeSAPO-34 components (CZZ/MeSAPO-34 catalyst) was then effectively utilized in a tandem catalytic process for one-step CO2hydrogenation to liquefied petroleum gas (LPG). The CZZ/MeSAPO-34 catalysts were characterized by using XRD, H2-TPR, BET, SEM-EDS and NH3-TPD techniques. SEM-EDS and XRD results indicated that an appropriate amount of Zr metal loading induced minimum zeolite framework collapse compared to a similar amount of Mn and Zn, which was more favorable for higher activity. In addition, NH3-TPD results revealed that the acidity of SAPO-34 could be altered after impregnation with different metals in different quantities. Tuning the acid density and strength, together with adjusting the CZZ to MeSAPO-34 weight ratio, had a collectively critical effect on LPG selectivity. An effective hydrogenation microenvironment which favors lower alkane formation (C3-C4) was enhanced after the acidity of the molecular sieve was tuned. LPG selectivity could reach 86% over the CZZ/5% ZrSAPO-34 catalyst at 2 MPa, 350 °C, a W/F ratio of 6, a H2/CO2ratio of 3 and a weight ratio of 1.

Laser photofragmentation time-of-flight mass spectrometric study of acetophenone at 193 and 248 nm


, p. 7230 - 7241 (1997)

The photodissociation of acetophenone (C6H5COCH3) at 193 and 248 nm is studied using the time-of-flight mass spectrometric technique. It is found that the dissociation is dominated by processes (1) and (2): C6H5COCH3+hν→C6H5CO+CH3 (1), C6H5+CH3CO (2) and, C6H5CH3+CO. At 193 nm, processes (1) and (2) occur with comparable cross sections. The cross section for process (3) at 193 nm is estimated to be 3CO and C6H5CO radicals initially formed at 193 nm by processes (1) and (2) are found to undergo further dissociation according to processes (6) and (8). At 248 nm, process (1) is overwhelmingly the dominant channel. The branching ratios for process (1) : process (2) : process (3) are estimated as 1.0:0.01:0.0008. The energy releases for these dissociation processes are also determined.

A Monolithically Integrated Gallium Nitride Nanowire/Silicon Solar Cell Photocathode for Selective Carbon Dioxide Reduction to Methane

Wang, Yichen,Fan, Shizhao,AlOtaibi, Bandar,Wang, Yongjie,Li, Lu,Mi, Zetian

, p. 8809 - 8813 (2016)

A gallium nitride nanowire/silicon solar cell photocathode for the photoreduction of carbon dioxide (CO2) is demonstrated. Such a monolithically integrated nanowire/solar cell photocathode offers several unique advantages, including the absorpt

Comparative study of CO2 hydrogenation to methanol on cubic bixbyite-type and rhombohedral corundum-type indium oxide

Yang, Bin,Li, Longtai,Jia, Ziye,Liu, Xiping,Zhang, Chunjie,Guo, Limin

, p. 2627 - 2633 (2020)

Hydrogenation of CO2 to value-added chemicals has attracted much attention all through the world. In2O3 with cubic bixbyite-type (denoted as c-In2O3) is well known for its high CO2 hydrogenation activity and CH3OH selectivity at high temperature. However, the other structure of In2O3 with rhombohedral corundum-type (denoted as rh-In2O3) rarely been investigated as catalyst. Herein, c-In2O3 and rh-In2O3 were prepared and comparatively studied for CO2 hydrogenation. The results indicated that c-In2O3 showed higher CO2 conversion activity than rh-In2O3 due to the impressive reducibility and reactivity. Whereas rh-In2O3 had higher CH3OH selectivity due to weaker CH3OH and stronger CO adsorption on rh-In2O3. Although c-In2O3 and rh-In2O3 catalysts showed different CO2 hydrogenation performance, in-situ diffuse reflectance infrared Fourier transform spectroscopy showed CO2 can be reduced to CO through redox cycling and hydrogenation to CH3OH through formate path.

Joint experimental and DFT study of the gas-phase unimolecular elimination kinetic of methyl trifluoropyruvate

Tosta, Maria M.,Mora, Jose R.,Cordova, Tania,Chuchani, Gabriel

, p. 7892 - 7897 (2010)

The elimination kinetics of methyl trifluoropyruvate in the gas phase was determined in a static system, where the reaction vessel was always deactivated with allyl bromide, and in the presence of at least a 3-fold excess of the free-radical chain inhibitor toluene. The working temperature range was 388.5-430.1 °C, and the pressure range was 38.6-65.8 Torr. The reaction was found to be homogeneous and unimolecular and to obey a first-order rate law. The products of the reaction are methyl trifluoroacetate and CO gas. The Arrhenius equation of this elimination was found to be as follows: log k1 (s-1) = (12.48 ± 0.32) - (204.2 ± 4.2) kJ mol -1(2.303RT)-1 (r = 0.9994). The theoretical calculation of the kinetic and thermodynamic parameters and the mechanism of this reaction were carried out at the B3LYP/6-31G(d,p), B3LYP/6-31++G(d,p), MPW1PW91/6-31G(d,p), MPW1PW91/6-31++G(d,p), PBEPBE/6-31G(d,p), and PBEPBE/6-31G++(d,p) levels of theory. The theoretical study showed that the preferred reaction channel is a 1,2-migration of OCH3 involving a three-membered cyclic transition state in the rate-determining step.

Lewis Acid Strength of Interfacial Metal Sites Drives CH3OH Selectivity and Formation Rates on Cu-Based CO2 Hydrogenation Catalysts

Noh, Gina,Lam, Erwin,Bregante, Daniel T.,Meyet, Jordan,?ot, Petr,Flaherty, David W.,Copéret, Christophe

, p. 9650 - 9659 (2021)

CH3OH formation rates in CO2 hydrogenation on Cu-based catalysts sensitively depend on the nature of the support and the presence of promoters. In this context, Cu nanoparticles supported on tailored supports (highly dispersed M on SiO2; M=Ti, Zr, Hf, Nb, Ta) were prepared via surface organometallic chemistry, and their catalytic performance was systematically investigated for CO2 hydrogenation to CH3OH. The presence of Lewis acid sites enhances CH3OH formation rate, likely originating from stabilization of formate and methoxy surface intermediates at the periphery of Cu nanoparticles, as evidenced by metrics of Lewis acid strength and detection of surface intermediates. The stabilization of surface intermediates depends on the strength of Lewis acid M sites, described by pyridine adsorption enthalpies and 13C chemical shifts of -OCH3 coordinated to M; these chemical shifts are demonstrated here to be a molecular descriptor for Lewis acid strength and reactivity in CO2 hydrogenation.

Photocatalytic C-C coupling from carbon dioxide reduction on copper oxide with mixed-valence copper(I)/copper(II)

Wang, Wei,Deng, Chaoyuan,Xie, Shijie,Li, Yangfan,Zhang, Wanyi,Sheng, Hua,Chen, Chuncheng,Zhao, Jincai

, p. 2984 - 2993 (2021)

To realize the evolution of C2+ hydrocarbons like C2H4 from CO2 reduction in photocatalytic systems remains a great challenge, owing to the gap between the relatively lower efficiency of multielectron transfer in photocatalysis and the sluggish kinetics of C-C coupling. Herein, with Cu-doped zeolitic imidazolate framework-8 (ZIF-8) as a precursor, a hybrid photocatalyst (CuOX@p-ZnO) with CuOX uniformly dispersed among polycrystalline ZnO was synthesized. Upon illumination, the catalyst exhibited the ability to reduce CO2 to C2H4 with a 32.9% selectivity, and the evolution rate was 2.7 μmol·g-1·h-1 with water as a hole scavenger and as high as 22.3 μmol·g-1·h-1 in the presence of triethylamine as a sacrificial agent, all of which have rarely been achieved in photocatalytic systems. The X-ray absorption fine structure spectra coupled with in situ FT-IR studies reveal that, in the original catalyst, Cu mainly existed in the form of CuO, while a unique Cu+ surface layer upon the CuO matrix was formed during the photocatalytic reaction, and this surface Cu+ site is the active site to anchor the in situ generated CO and further perform C-C coupling to form C2H4. The C-C coupling intermediate *OC-COH was experimentally identified by in situ FT-IR studies for the first time during photocatalytic CO2 reduction. Moreover, theoretical calculations further showed the critical role of such Cu+ sites in strengthening the binding of *CO and stabilizing the C-C coupling intermediate. This work uncovers a new paradigm to achieve the reduction of CO2 to C2+ hydrocarbons in a photocatalytic system.

An Investigation of the end-products of CO2-laser irradiation of the ethene gas

Nemes, L.,Szekely, T.

, p. 243 - 244 (1987)


UV photodissociation of oxalyl chloride yields four fragments from one photon absorption

Ahmed, Musahid,Blunt, David,Chen, Daniel,Suits, Arthur G.

, p. 7617 - 7624 (1996)

The photodissociation of oxalyl chloride, (ClCO)2, has been studied near 235 nm using the photofragment imaging technique. Observed products include both ground state Cl (2P3/2) and spin-orbit excited Cl*(2P1/2) chlorine atoms and ground electronic state CO molecules. The rotational distribution obtained for the CO v=0 product is peaked at about J=30 and extends beyond J=50. Photofragment images were recorded for both chlorine atom fine structure components as well as many rotational levels of the CO v=0, yielding state-resolved angular and translational energy distributions. The recoil speed distribution for the Cl* exhibits a dominant fast component, with a translational energy distribution peaking at about 48 kJ/mol. The ground state chlorine atom showed two components in its speed distribution, with the slow component dominant. The corresponding translational energy distribution peaked at 10 kJ/mol but extended to 80 kJ/mol. The total average translational energy release into the Cl product is 34 kJ/mol. Similarly, the low rotational levels of the CO showed only a slow component, the intermediate rotational levels showed a bimodal speed distribution, and the highest rotational levels showed only the fast component. The fast components of both chlorine atom product and the higher rotational levels of the CO show an anisotropic angular distribution, while all slow fragments show a nearly isotropic angular distribution. These observations suggest a novel dissociation mechanism in which the first step is an impulsive three-body dissociation yielding predominantly Cl*, rotationally excited CO and chloroformyl radical ClCO, with only modest momentum transfer to the latter species. Most of the remaining ClCO undergoes subsequent dissociation yielding low rotational levels of CO and little translational energy release.

Oxidation of Allyl Radicals: Kinetic Parameters for the Reactions of Allyl Radicals with HO2 and O2 between 400 and 480 deg C

Lodhi, Zulfiqar H.,Walker, Raymond W.

, p. 2361 - 2365 (1991)

The decomposition of 4,4-dimethylpent-1-ene (DMP) in the presence of O2 has been used as a source of allyl and HO2 radicals between 400 and 480 deg C.Propene was added to the mixtures of DMP and O2 in order to monitor from the yields of propene oxide by use of the known value of k14.HO2 + C3H6 -> C3H6O + OH (14).From measurements of the initial yields of CO, hexa-1,5-diene and propene oxide over a range of mixture composition, rate constants have been obtained for reaction (9) and (10). CH2CHCH2 + HO2 -> CO + product (9); CH2CHCH2 + HO2 -> C3H6 + HO2 (10).At 400 deg C, k9 = 3.95 x 109 and k10 = 1.42 x 109 dm3 mol-1 s-1 and both show a slight increase (within experimental error) with temperature, 15percent and 30percent, repectively, at 480 deg C.Strong evidence is obtained for the formation of CO in the reaction between allyl radicals and O2 and values of A15 = 109.4 +/- 0.6 dm3 mol-1 s-1 and E15 = 79 +/- 8 kJ mol-1 are obtained. CH2CHCH2 + O2 -> CO + products (15).The mechanism of reactions (10) and (15) are discussed.Based on current thermochemistry it is shown by calculation that reaction (10) probably occurs only to a minor extent through a direct H-atom abstraction route which is reverse of the chain initiation reaction (16).C3H6 + O2 -> CH2CHCH2 + HO2 (16).The available kinetic data for the reaction between allyl radicals and O2 are summarised.

Self-growth-templating synthesis of 3D N,P,Co-doped mesoporous carbon frameworks for efficient bifunctional oxygen and carbon dioxide electroreduction

Pan, Fuping,Liang, Aimin,Duan, Youxin,Liu, Qiao,Zhang, Junyan,Li, Ying

, p. 13104 - 13111 (2017)

Although mesopore designs are expected to play a key role in exploring electrocatalytic properties of carbons, facile preparation of mesoporous carbons (MPCs) with efficient dopants to enable high performance remains a great challenge. Herein, we for the

Effect of active and inert oxide on catalytic partial oxidation (CPO) of methane over supported Ni catalysts

LaParola, V.,Pantaleo, G.,Venezia, Anna

, (2021/11/27)

The effects of preparation method, types of carrier and different catalyst and support structures on the CH4 catalytic partial oxidation (CPO) activity of supported Ni catalysts are reviewed with respect to selected results obtained by this research group during the last five years. In particular, different preparation methods and structural effect of Ni supported on La2O3, on CeO2 and on mixed CeO2-La2O3 are discussed. The effects of the peculiarity of an active (redox) and of an inert oxide carrier, influencing the metal dispersion, the metal reducibility and the carbon formation, are considered by comparing the catalytic performance of nickel catalysts supported on CeO2 and on SiO2. Ni supported over a high surface area silica will be compared with a corresponding ceria-doped nickel catalyst. The results of a detailed material characterization attained by several techniques as XPS, XRD, TPR/TPO are described, aiming to elucidate the structure - activity relationship. The reviewing of the different case studies illustrates the importance of the interaction between support and active metals ultimately determining the surface distribution of the active sites and their final catalytic activity.

Rapid alloying of Au–Pd nanospheres by a facile pulsed laser technique: Insights into a molar-dependent electrocatalytic methanol oxidation reaction

Chinnadurai, Deviprasath,Choi, Myong Yong,Lee, Seung Jun,Lee, Young Wook,Yeon, Sanghun,Yu, Yiseul

, (2021/10/04)

Direct methanol fuel cells have attracted extensive research interest because of their relatively high energy density and portability. It is important to rationally design the composition and surface atomic structure by efficient synthesis protocols to boost cell efficiency. In this study, we employed cohesive pulsed laser irradiation and ultrasonochemical techniques to synthesize and tune the molar ratio of an Au–Pd alloy for the methanol oxidation reaction (MOR). The effective implementation of extremely rapid photoinduced reduction and reaction conditions resulted in the formation of well-dispersed and homogenous nanospheres of the Au–Pd alloy with uniform particle size. Moreover, the composition-tuned Au–Pd alloy exhibited an improved electrocatalytic activity, which might be due to its improved electrical conductivity and higher CO tolerance. The alloy achieved relatively high mass and specific activities of 0.50 A/mgPd and 1.36 mA/cmPd2, respectively. Additionally, we studied the effect of the Au–Pd composition on the MOR activity and analyzed the reaction kinetics in depth. This work provides the foundation for implementing a laser-based technique to synthesize Pd-based alloy electrocatalysts for MOR application.

Oxygen-vacancy generation in MgFe2O4 by high temperature calcination and its improved photocatalytic activity for CO2 reduction

Chen, Haowen,Fu, Liming,Wang, Kang,Wang, Xitao

, (2021/09/28)

MgFe2O4 spinel with abundant oxygen vacancy was synthesized by a simple precipitation method, and tested in photocatalytic reduction of CO2 with water vapor as reductant. A series of characterization including XRD, XPS, EPR, PL spectrum, UV–vis DRS and TPD-CO2 were performed to investigate the influence of calcination temperature on morphology, optical and electronic properties of MgFe2O4 spinel. The results demonstrated that the oxygen vacancy concentration increases first and then decreases with the increase of calcination temperature. By introducing oxygen vacancies, the recombination of photogenerated electron-hole pairs was significantly suppressed, visible light absorption and chemisorption capacity of CO2 were dramatically boosted. Mg-Fe-750 with the richest oxygen vacancies exhibits the highest photocatalytic activity, for which the production rate of CO and H2 was 24.4 and 34.3 μmol/gcat/h, respectively.

Ethanol Steam Reforming by Ni Catalysts for H2 Production: Evaluation of Gd Effect in CeO2 Support

Assaf, Elisabete M.,Ferreira, Gabriella R.,Lucrédio, Alessandra F.,Nogueira, Francisco G. E.

, (2022/01/19)

Abstract: Ni-based catalysts supported on CeO2 doped with Gd were prepared in this work to investigate the role of gadolinium on ethanol conversion, H2 selectivity, and carbon formation on ethanol steam reforming reaction. For this, catalysts containing 5 wt% of Ni impregnated on supports of ceria modified with different amounts of Gd (1, 5, and 10 wt%) were used. Ex-situ studies of XRPD suggest an increase of the lattice parameters, indicating a solid solution formation between Gd and Ce. Results of TPR showed an increase in metal-support interactions as the content of Gd increased. In situ XRPD studies indicated the formation of a GdNiO ternary phase for the catalysts containing Gd, which is in agreement with the results obtained by XANES. The catalysts were tested at three temperatures: 400?°C, 500?°C, and 600?°C. The conversion and productivity showed dependence with the Gd content and also with the temperature of the reaction. After the catalytic tests, catalysts containing Gd presented filamentous carbon possible due to a change in the reaction pathway. The highest ethanol conversion and H2 productivity were obtained at 600?°C for all catalysts and the best catalyst at this temperature was 5Ni_5GdCeO2. The promising performance of this catalyst may be associate with the lowest formation of GdNiO ternary phase, among the catalysts containing Gd, which means more Ni0 active species available to convert ethanol. Graphical Abstract: [Figure not available: see fulltext.]

Rational Design of Zinc/Zeolite Catalyst: Selective Formation of p-Xylene from Methanol to Aromatics Reaction

Chen, Biaohua,Chen, Congmei,Chen, Xiao,Hou, Yilin,Hu, Xiaomin,Li, Jing,Qian, Weizhong,Sun, Wenjing,Wang, Ning,Yang, Yifeng,Zhang, Lan

supporting information, (2022/02/16)

The production of p-xylene from the methanol to aromatics (MTA) reaction is challenging. The catalytic stability, which is inversely proportional to the particle size of the zeolite, is not always compatible with p-xylene selectivity, which is inversely proportional to the external acid sites. In this study, based on a nano-sized zeolite, we designed hollow triple-shelled Zn/MFI single crystals using the ultra-dilute liquid-phase growth technique. The obtained composites possessed one ZSM-5 layer (≈30 nm) in the middle and two silicalite-1 layers (≈20 nm) epitaxially grown on two sides of ZSM-5, which exhibited a considerably long lifetime (100 % methanol conversion >40 h) as well as an enhanced shape selectivity of p-xylene (>35 %) with a p-xylene/xylene ratio of ≈90 %. Importantly, using this sandwich-like zeolite structure, we directly imaged the Zn species in the micropores of only the ZSM-5 layer and further determined the specific structure and anchor location of the Zn species.

Process route upstream and downstream products

Process route







carbon monoxide

carbon monoxide

Conditions Yield
at 149.9 ℃; under 28.5 Torr; Product distribution; Quantum yield; Mechanism; Irradiation; mercury-photosensitized decomposition; other pressures (640 - 5000 Pa), different light intensities;
carbon monoxide

carbon monoxide



Conditions Yield
With oxygen; at 850 ℃; for 24h; under 760.051 Torr; Reagent/catalyst; Temperature; Time; Catalytic behavior; Flow reactor;
With oxygen; at 850 ℃; for 24h; under 760.051 Torr; Reagent/catalyst; Flow reactor;
With oxygen; at 850 ℃; for 24h; under 760.051 Torr; Flow reactor;
With oxygen; ytterbium(III) oxide; nickel; at 700 ℃; Product distribution; variation of conditions, also with NiO/Yb2O3;
With oxygen; at 850 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; Mg0.97Ni0.03O; at 830 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; Mg0.95Ni0.03ORh0.02; at 810 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; nickel aluminate; at 725 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; LaNi0.5O3Zr0.5; at 875 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; at 300 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; at 360 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; at 820 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; at 720 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; at 650 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; at 700 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; at 795 ℃; under 1020.1 Torr; Conversion of starting material;
With oxygen; Rh/Sm; at 300 ℃; for 45.5h; under 3090.31 - 5415.54 Torr; Conversion of starting material;
With water;
With water; alumina coating-platinum/rhodium; at 450 - 869 ℃; Conversion of starting material;
With oxygen; ATR catalyst; at 421.101 - 476.657 ℃; under 3863.02 Torr; Product distribution / selectivity; Gas phase;
With oxygen; Product distribution / selectivity;
With oxygen; Fe0.7LaNi0.25O3Rh0.05; at 500 - 867 ℃; under 760.051 Torr; Conversion of starting material;
With oxygen; Ce0.2Fe0.7La0.8Ni0.25O3Rh0.05; at 500 - 890 ℃; under 760.051 Torr; Conversion of starting material;
With oxygen; Fe0.7LaNi0.3O3; at 500 - 872 ℃; under 760.051 Torr; Conversion of starting material;
With oxygen; Fe0.95LaO3Rh0.05; at 500 - 827 ℃; under 760.051 Torr; Conversion of starting material;
gallium(III) oxide; In neat (no solvent); Irradiation (UV/VIS); 220-300 nm, 314 K, 3 h; C2H6, C2H4, C3H8, C4H10 and traces of C3H6 were also formed;
gallium(III) oxide; In neat (no solvent); Irradiation (UV/VIS); 220-300 nm, 473 K, 3 h; C2H6, C2H4, C3H8, C4H10 and C3H6 were also formed;
With air; In gas; byproducts: CO2, H2O; mixt. of CH4, air passed through the membrane of Ba0.5Sr0.5Co0.8Fe0.2O(3-δ), Co3O4 and then through catalyst - Ni/γ-Al3O3;
With air; copper(II) oxide; at atm. pressure in fixed-bed U-shaped cylindrical quartz reactor at temps. from 350 to 800°C;
With air; nickel(II) oxide; at atm. pressure in fixed-bed U-shaped cylindrical quartz reactor at temps. from 350 to 800°C;
With air; (NiO)2(UO3); at atm. pressure in fixed-bed U-shaped cylindrical quartz reactor at temps. from 350 to 800°C;
With air; (CuO)2(ThO2); at atm. pressure in fixed-bed U-shaped cylindrical quartz reactor at temps. from 350 to 800°C;
With air; (NiO)2(ThO2); at atm. pressure in fixed-bed U-shaped cylindrical quartz reactor at temps. from 350 to 800°C;
With air; catalyst: Pt/Al2O3; at atm. pressure in fixed-bed U-shaped cylindrical quartz reactor at temps. from 350 to 800°C;
With oxygen; at 700 ℃; under 3 Torr; Reagent/catalyst; Temperature; Inert atmosphere;
With Cu0.7(Al2O3)0.3; water;
With mesoporous silica support was impregnated with [μ-(acetato-kO:kO')]bis(acetato-kO)-tetrakis{μ3-[di(2-pyridinyl-kN)methanediolato-kO:kO:kO]}tetra-nickel(II) perchlorate hydrate; at 600 ℃; Reagent/catalyst;
With oxygen; at 800 ℃; under 760.051 Torr; Temperature; Reagent/catalyst; Catalytic behavior; Inert atmosphere; Flow reactor; Gas phase;
With sodium zirconate; carbon dioxide; at 200 - 900 ℃; Temperature; Inert atmosphere;
With carbon dioxide; In neat (no solvent, gas phase); at 650 ℃; Reagent/catalyst; Catalytic behavior; Kinetics; Inert atmosphere;
With oxygen; at 750 ℃; Temperature;
With carbon dioxide; at 850 ℃; Reagent/catalyst; Kinetics; Flow reactor;
With carbon dioxide; UV-irradiation;
Conditions Yield
With oxygen; 0.7percentK2O-15percentMoO3/SiO2-TiO2; at 450 - 495 ℃; Product distribution / selectivity;
With oxygen; 0.7percentK2O-15percentMoO3/SiO2-TiO2 on microgrooved support; at 395 - 454 ℃; Product distribution / selectivity;
With water; oxygen; vanadia; magnesium oxide; at 499.9 ℃; under 760 Torr; Product distribution; other catalysts; other temp.;
With aluminium oxide vanadium(V)-oxide catalyst; oxygen; at 500 ℃; var. V2O5-Al2O3 ratio, also withouth O2;
4-nitrophenoxyacetic acid

4-nitrophenoxyacetic acid

carbon dioxide

carbon dioxide

carbon monoxide

carbon monoxide

Conditions Yield
With pyridinium hydrobromide perbromide; acetic acid; at 19.9 ℃; Rate constant; Kinetics; Thermodynamic data; ΔH(activ.), ΔS(activ.); var. temperature;
tribromoacetic acid

tribromoacetic acid

tribromoacrylic acid

tribromoacrylic acid

carbon dioxide

carbon dioxide

carbon monoxide

carbon monoxide

hydrogen bromide

hydrogen bromide

Conditions Yield
With sodium hydroxide; formaldehyd; dinitrogen monoxide; In water; at 22 ℃; for 24h; pH=10; Further Variations:; Reagents; Temperatures; G-values; γ-Irradiation;
(RS)-2-(4-nitrophenoxy)propionic acid

(RS)-2-(4-nitrophenoxy)propionic acid

carbon monoxide

carbon monoxide



Conditions Yield
at 326.85 ℃; Kinetics;
4-nitrophenoxyacetic acid

4-nitrophenoxyacetic acid

carbon monoxide

carbon monoxide

Conditions Yield
at 291.05 - 338.35 ℃; Kinetics;
Conditions Yield
With oxygen; Al0.4Co1.6La0.6O5.3Sr1.4; at 700 ℃; for 0.00833333 - 0.0833333h; Product distribution / selectivity;
With water; at 600 ℃; for 5h; Reagent/catalyst;
With water; Reagent/catalyst; Inert atmosphere;
carbon dioxide

carbon dioxide



carbon monoxide

carbon monoxide



Conditions Yield
at 850 - 950 ℃; under 18389.3 Torr;
at 700 - 1050 ℃; under 14711.4 - 18389.3 Torr;
nickel; heterogeneous oxidn. of methane with oxygene and with CO2, 520-535 °C, 60 % CH4, 35 % O2, 5 % CO2;
With lanthanum nickelate; at 600 - 800 ℃; Catalytic behavior; Kinetics; Inert atmosphere;




carbon monoxide

carbon monoxide



Conditions Yield
With water; nickel based catalysts and noble metals; at 200 - 1050 ℃;
methane; ethane; propane; With water; at 480 - 750 ℃; under 27227.7 - 32853.3 Torr; Industry scale;
With oxygen; at 702 - 1000 ℃; under 26327.6 - 27227.7 Torr; Industry scale;

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