64-17-5Relevant articles and documents
An efficient Ni-Mo-K sulfide catalyst doped with CNTs for conversion of syngas to ethanol and higher alcohols
Wang, Ji-Jie,Xie, Jian-Rong,Huang, Yan-Hui,Chen, Bing-Hui,Lin, Guo-Dong,Zhang, Hong-Bin
, p. 44 - 51 (2013)
A type of Ni-Mo-K sulfide catalyst doped with CNTs for conversion of syngas to ethanol and higher alcohols was developed, and displayed high activity and selectivity for direct synthesis of C1-4-alcohols, especially ethanol, from syngas. Over a Ni0.5Mo1K0.5- 15%CNTs catalyst under the reaction conditions of 8.0 MPa and 593 K, the S(total oxy.) reached 64.1% (CO2-free), with the corresponding STY(total oxy.) being 113 mg h-1 g-1. Ethanol was the dominant product, with S(EtOH) and STY(EtOH) reaching 33.1% (CO2-free) and 55.6 mg h-1 g-1, respectively. This STY(EtOH)-value was 1.47 times that (37.9 mg h-1 g-1) of the CNTs-free counterpart under the same reaction conditions. Addition of a minor amount of CNTs to the sulfurized Ni0.5Mo1K0.5 catalyst caused little change in the Ea for the hydrogenation-conversion of syngas. Appropriately reducing CNT's grain-size could improve its capability to adsorb hydrogen, thus increasing CO hydrogenation-conversion, yet did not influence selectivity of the products. The present work demonstrated that CNTs as promoter function through their adsorbing/activating H2 to generate a surface micro-environment with higher stationary-state concentration of H-adspecies on the functioning catalyst. This resulted in a dramatic increase, at the surface of the functioning catalyst, of the molar percentage of catalytically active Mo4+/Mo5+ species in the total amounts of surface Mo. On the other hand, those active H-species adsorbed at the CNTs surface could be readily transferred to NiiMojK k active sites via the CNT-assisted hydrogen spillover. The aforementioned two factors both were conducive to increasing the rate of hydrogenation conversion of syngas.
Enhanced catalytic activity of Au core Pd shell Pt cluster trimetallic nanorods for CO2 reduction
He, Lan-Qi,Yang, Hao,Huang, Jia-Jun,Lu, Xi-Hong,Li, Gao-Ren,Liu, Xiao-Qing,Fang, Ping-Ping,Tong, Ye-Xiang
, p. 10168 - 10173 (2019)
Herein, Au core Pd shell Pt cluster nanorods (Au@Pd@Pt NRs) with enhanced catalytic activity were rationally designed for carbon dioxide (CO2) reduction. The surface composition and Pd-Pt ratios significantly influenced the catalytic activity, and the optimized structure had only a half-monolayer equivalent of Pt (Pt = 0.5) with 2 monolayers of Pd, which could enhance the catalytic activity for CO2 reduction by 6 fold as compared to the Pt surface at -1.5 V vs. SCE. A further increase in the loading of Pt actually reduced the catalytic activity; this inferred that a synergistic effect existed among the three different nanostructure components. Furthermore, these Au NRs could be employed to improve the photoelectrocatalytic activity by 30% at -1.5 V due to the surface plasmon resonance. An in situ SERS investigation inferred that the Au@Pd@Pt NRs (Pt = 0.5) were less likely to be poisoned by CO because of the Pd-Pt bimetal edge sites; due to this reason, the proposed structure exhibited highest catalytic activity. These results play an important role in the mechanistic studies of CO2 reduction and offer a new way to design new materials for the conversion of CO2 to liquid fuels.
Production of bio-ethanol by consecutive hydrogenolysis of corn-stalk cellulose
Chu, Dawang,Xin, Yingying,Zhao, Chen
, p. 844 - 854 (2021)
Current bio-ethanol production entails the enzymatic depolymerization of cellulose, but this process shows low efficiency and poor economy. In this work, we developed a consecutive aqueous hydrogenolysis process for the conversion of corn-stalk cellulose to produce a relatively high concentration of bio-ethanol (6.1 wt%) without humin formation. A high yield of cellulose (ca. 50 wt%) is extracted from corn stalk using a green solvent (80 wt% 1,4-butanediol) without destroying the structure of the lignin. The first hydrothermal hydrogenolysis step uses a Ni–WOx/SiO2 catalyst to convert the high cumulative concentration of cellulose (30 wt%) into a polyol mixture with a 56.5 C% yield of ethylene glycol (EG). The original polyol mixture is then subjected to subsequent selective aqueous-phase hydrogenolysis of the C–O bond to produce bioethanol (75% conversion, 84 C% selectivity) over the modified hydrothermally stable Cu catalysts. The added Ni component favors the good dispersion of Cu nanoparticles, and the incorporated Au3+ helps to stabilize the active Cu0-Cu+ species. This multi-functional catalytic process provides an economically competitive route for the production of cellulosic ethanol from raw lignocellulose.
Highly Selective Electrochemical Reduction of CO2 to Alcohols on an FeP Nanoarray
Ji, Lei,Li, Lei,Ji, Xuqiang,Zhang, Ya,Mou, Shiyong,Wu, Tongwei,Liu, Qian,Li, Baihai,Zhu, Xiaojuan,Luo, Yonglan,Shi, Xifeng,Asiri, Abdullah M.,Sun, Xuping
, p. 758 - 762 (2020)
Electrochemical reduction of CO2 into various chemicals and fuels provides an attractive pathway for environmental and energy sustainability. It is now shown that a FeP nanoarray on Ti mesh (FeP NA/TM) acts as an efficient 3D catalyst electrode for the CO2 reduction reaction to convert CO2 into alcohols with high selectivity. In 0.5 m KHCO3, such FeP NA/TM is capable of achieving a high Faradaic efficiency (FECH3OH) up to 80.2 %, with a total FE FECH3OH+C2H5OH of 94.3 % at ?0.20 V vs. reversible hydrogen electrode. Density functional theory calculations reveal that the FeP(211) surface significantly promotes the adsorption and reduction of CO2 toward CH3OH owing to the synergistic effect of two adjacent Fe atoms, and the potential-determining step is the hydrogenation process of *CO.
Acetaldehyde as an Intermediate in the Electroreduction of Carbon Monoxide to Ethanol on Oxide-Derived Copper
Bertheussen, Erlend,Verdaguer-Casadevall, Arnau,Ravasio, Davide,Montoya, Joseph H.,Trimarco, Daniel B.,Roy, Claudie,Meier, Sebastian,Wendland, Jürgen,N?rskov, Jens K.,Stephens, Ifan E. L.,Chorkendorff
, p. 1450 - 1454 (2016)
Oxide-derived copper (OD-Cu) electrodes exhibit unprecedented CO reduction performance towards liquid fuels, producing ethanol and acetate with >50% Faradaic efficiency at -0.3 V (vs. RHE). By using static headspace-gas chromatography for liquid phase analysis, we identify acetaldehyde as a minor product and key intermediate in the electroreduction of CO to ethanol on OD-Cu electrodes. Acetaldehyde is produced with a Faradaic efficiency of ≈5% at -0.33 V (vs. RHE). We show that acetaldehyde forms at low steady-state concentrations, and that free acetaldehyde is difficult to detect in alkaline solutions using NMR spectroscopy, requiring alternative methods for detection and quantification. Our results represent an important step towards understanding the CO reduction mechanism on OD-Cu electrodes.
Photochemical Preparation of Anatase Titania Supported Gold Catalyst for Ethanol Synthesis from CO2 Hydrogenation
Wang, Dong,Bi, Qingyuan,Yin, Guoheng,Wang, Peng,Huang, Fuqiang,Xie, Xiaoming,Jiang, Mianheng
, p. 11 - 22 (2018)
Abstract: Hydrogenation of the greenhouse gas CO2 to higher alcohols through catalysis holds great promise for resource transformation in low-carbon energy supply system, but the efficient and selective synthesis of value-added ethanol by a robust heterogeneous catalyst under relatively mild conditions remains a major challenge. Based on our previous work on Au/TiO2 as an active and selective catalyst for ethanol synthesis, we report here that a facile photochemical route can be used for the preparation of anatase TiO2 supported gold catalyst (Au/a-TiO2) for efficient hydrogenation of CO2. Compared with the conventional deposition-precipitation method requiring strong br?nsted base and flammable H2 gas in the complicated and time-consuming process, the photochemical way for the facile preparation of supported gold catalyst shows the advantages of green and energy-saving. Of significant importance is that an impressive space-time-yield of 869.3?mmol?gAu?1?h?1, high selectivity, and excellent stability can be readily attained at 200?°C and total pressure of 6?MPa. The effects of irradiation time, solvent, and metal loading or Au particle size on ethanol synthesis are systematically investigated. Graphical Abstract: [Figure not available: see fulltext.].
Hydrolysis and Condensation Reactions of Transition Metal Alkoxides: Calorimetric Study and Evaluation of the Extent of Reaction
Blanchard, Juliette,In, Martin,Schaudel, Barbara,Sanchez, Clement
, p. 1115 - 1127 (1998)
The behavior of titanium and zirconium alkoxides towards complexation and water addition is analyzed through water titration and calorimetric experiments. A simple model is presented, which allows evaluation of the mean hydrolysis and condensation constan
Fe/Fe3C Boosts H2O2 Utilization for Methane Conversion Overwhelming O2 Generation
Xing, Yicheng,Yao, Zheng,Li, Wenyuan,Wu, Wenting,Lu, Xiaoqing,Tian, Jun,Li, Zhongtao,Hu, Han,Wu, Mingbo
, p. 8889 - 8895 (2021)
H2O2 as a well-known efficient oxidant is widely used in the chemical industry mainly because of its homolytic cleavage into .OH (stronger oxidant), but this reaction always competes with O2 generation resulting in H2O2 waste. Here, we fabricate heterogeneous Fenton-type Fe-based catalysts containing Fe-Nx sites and Fe/Fe3C nanoparticles as a model to study this competition. Fe-Nx in the low spin state provides the active site for .OH generation. Fe/Fe3C, in particular Fe3C, promotes Fe-Nx sites for the homolytic cleavages of H2O2 into .OH, but Fe/Fe3C nanoparticles (Fe0 as the main component) with more electrons are prone to the undesired O2 generation. With a catalyst benefiting from finely tuned active sites, 18 % conversion rate for the selective oxidation of methane was achieved with about 96 % selectivity for liquid oxygenates (formic acid selectivity over 90 %). Importantly, O2 generation was suppressed 68 %. This work provides guidance for the efficient utilization of H2O2 in the chemical industry.
Acidic 1,3-propanediaminetetraacetato lanthanides with luminescent and catalytic ester hydrolysis properties
Chen, Mao-Long,Shi, Yan-Ru,Yang, Yu-Chen,Zhou, Zhao-Hui
, p. 265 - 273 (2014)
In acidic solution, a serials of water-soluble coordination polymers (CPs) were isolated as zonal 1D-CPs 1,3-propanediaminetetraacetato lanthanides [Ln(1,3-H3pdta)(H2O)5]n· 2Cln·3nH2O [Ln=La, 1; Ce, 2; Pr, 3; Nd, 4; Sm, 5] (1,3-H4pdta=1,3-propanediaminetetraacetic acid, C11H 18N2O8) in high yields. When 1 eq. mol potassium hydroxide was added to the solutions of 1D-CPs, respectively, two 1D-CPs [Ln(1,3-H2pdta)(H2O)3] n·Cln·2nH2O [Ln=Sm, 6; Gd, 7] were isolated at room temperature and seven 2D-CPs [Ln(1,3-H2pdta) (H2O)2]n·Cln·2nH 2O [Ln=La, 8; Ce, 9; Pr, 10; Nd, 11; Sm, 12; Eu, 13; Gd, 14] were isolated at 70 °C. When the crystals of 1-4 were hydrothermally heated at 180 °C with 1-2 eq. mol potassium hydroxide, four 3D-CPs [Ln(1,3-Hpdta)]n·nH2O [Ln=La, 15; Ce, 16; Pr, 17; Nd, 18] were obtained. The two 2D-CPs [Ln(1,3-Hpdta)(H2O)] n·4nH2O (Sm, 19; Eu, 20) were isolated in similar reaction conditions. With the increments of pH value in the solution and reaction temperature, the structure becomes more complicated. 1-5 are soluble in water and 1 was traced by solution 13C{1H} NMR technique, the water-soluble lanthanides 1 and 5 show catalytic activity to ester hydrolysis reaction respectively, which indicate their important roles in the hydrolytic reaction. The europium complexes 13 and 20 show visible fluorescence at an excitation of 394 nm. The structure diversity is mainly caused by the variation of coordinated ligand in different pH values and lanthanide contraction effect. Acidic conditions are favorable for the isolations of lanthanide complexes in different structures and this may helpful to separate different lanthanides. The thermal stability investigations reveal that acidic condition is favorable to obtain the oxides at a lower temperature.
Kinetics of hydrogenation of acetic acid to ethanol
Chen, Qiang,Zhang, Xuebing,Tian, Shuxun,Long, Junying,Meng, Xiangkun,Sun, Qi,Li, Yonglong
, p. 2915 - 2923 (2019)
The intrinsic kinetic behaviour of catalytic hydrogenation of acetic acid in vapour phase was studied over a multi-metallic catalyst. The rate expression was derived from the sequence of elementary reaction steps based on a Langmuir-Hinshelwood-model involving two types of active sites. Experiments were carried out in a fixed bed reactor, which is similar to an isothermal integral reactor designed to excluding the negative effects of internal and external diffusion. The reaction conditions investigated were as follow:reaction temperature 275-325 oC, reaction pressure1.5-3.0 MPa, liquid hourly space velocity (sv) 0.3-1.2 h-1, molar ratio of hydrogen to acetic acid (H/AC) 8:20. The results show that conversion of acetic acid increases with increasing the reaction temperature and pressure, but decreases with increasing the space velocity and H/AC. Furthermore, reducing the reaction pressure and increasing reaction temperature, space velocity and H/AC can improve the reaction selectivity of acetic acid to ethanol. The established kinetic model results agreed with experimental results. The relative difference between the calculated value and the experimental value is less than 6 %. The values of model parameters are consistent with the three thermodynamic constraints. The study provided evidence that the intrinsic kinetic model is suitable both mathematically and thermodynamically, and it could be useful in guiding reactor design and optimization of operating conditions.
