124-38-9Relevant articles and documents
CO activation pathways and the mechanism of Fischer-Tropsch synthesis
Ojeda, Manuel,Nabar, Rahul,Nilekar, Anand U.,Ishikawa, Akio,Mavrikakis, Manos,Iglesia, Enrique
, p. 287 - 297 (2010)
Unresolved mechanistic details of monomer formation in Fischer-Tropsch synthesis (FTS) and of its oxygen rejection routes are addressed here by combining kinetic and theoretical analyses of elementary steps on representative Fe and Co surfaces saturated w
Reactivity of Silanes with (tBuPONOP)Ruthenium Dichloride: Facile Synthesis of Chloro-Silyl Ruthenium Compounds and Formic Acid Decomposition
Anderson, Nickolas H.,Boncella, James M.,Tondreau, Aaron M.
, p. 13617 - 13622 (2017)
The coordination of tBuPONOP (tBuPONOP=2,6-bis(ditert-butylphosphinito)pyridine) to different ruthenium starting materials, to generate (tBuPONOP)RuCl2, was investigated. The resultant (tBuPONOP)RuCl
Photocatalytic reactions under irradiation of visible light over gold nanoparticles supported on titanium(IV) oxide powder prepared by using a multi-step photodeposition method
Tanaka, Atsuhiro,Sakaguchi, Satoshi,Hashimoto, Keiji,Kominami, Hiroshi
, p. 1931 - 1938 (2014)
Titanium(IV) oxide (TiO2) having both smaller and larger gold (Au) particles was successfully prepared by a multi-step (MS) photodeposition method. When 0.25 wt% Au loading per photodeposition was repeated four times, smaller and larger Au particles having average diameters of 1.4 and 13 nm, respectively, were fixed on TiO2, and the Au/TiO2 sample exhibited strong photoabsorption around 550 nm due to surface plasmon resonance (SPR) of the larger Au particles. Various Au/TiO2 samples were prepared by changing the Au loading per photodeposition and the number of photodepositions. Effects of the conditions in MS photodeposition and sample calcination on Au particle distribution and photoabsorption properties were investigated. These samples were used for hydrogen (H2) formation from 2-propanol and mineralization of acetic acid in aqueous suspensions under irradiation of visible light. In the case of H2 formation under deaerated conditions, the reaction rate of Au/TiO2 having both larger and smaller particles was 4 times higher than that of the Au/TiO2 sample without smaller Au particles, indicating that smaller Au particles acted effectively as a co-catalyst, that is, as reduction sites for H2 evolution. On the other hand, in the case of mineralization of acetic acid under aerated conditions, carbon dioxide formation rates were independent of the presence of smaller Au particles, indicating that the smaller Au particles had little effect on the mineralization of acetic acid. To extend the possibility of Au/TiO2 for H2 formation under irradiation of visible light, H2 formation from ammonia (NH3) as biomass waste was examined under deaerated conditions; NH3 was decomposed to H 2 and nitrogen with a stoichiometric ratio of 3:1. The Royal Society of Chemistry 2014.
Study on the kinetics of thermal decomposition of CaCO3
Wei,Luo
, p. 303 - 310 (1995)
By means of TG, the thermal decomposition of the powdered CaCO3 was tested with its various dispersities, range of size, and the different content of CO2 in flowing nitrogen. Formulae for calculating the rate and time of decomposition were obtained.
Autothermal reforming of CH4 over supported Ni catalysts prepared from Mg-Al hydrotalcite-like anionic clay
Takehira, Katsuomi,Shishido, Tetsuya,Wang, Peng,Kosaka, Tokuhisa,Takaki, Ken
, p. 43 - 54 (2004)
spc-Ni/MgAl (spc: solid-phase crystallization method) catalysts were prepared from Mg-Al hydrotalcite-like compounds containing Ni at the Mg site as the precursors and tested for partial oxidation of CH4 into synthesis gas. The activity of spc-
Synthesis of four-angle star-like CoAl-MMO/BiVO4 p-n heterojunction and its application in photocatalytic desulfurization
Yun, Limin,Yang, Zhanxu,Yu, Zong-Bao,Cai, Tianfeng,Li, Yue,Guo, Changyou,Qi, Chengyuan,Ren, Tieqiang
, p. 25455 - 25460 (2017)
A four-angle star-like Co-Al mixed metal oxide (CoAl-MMO)/BiVO4 heterojunction has been synthesized via a hydrothermal method and following sintering. The CoAl-MMO/BiVO4 is derived from CoAl-LDHs/BiVO4, in which CoAl-LDHs leads to a distribution of amorphous CoAl-MMO. The CoAl-MMO loading on BiVO4 greatly enhances visible light absorption, improves charge separation by band offset charge transfer, and makes flat band potential more negative. The three effects together result in excellent photocatalytic activity. Under visible light irradiation, desulfurization efficiency of thiophene has achieved up to 98.58% on CoAl-MMO/BiVO4 with molar ratio of 0.3:5.
Structure of surface tantalate species and photo-oxidation of carbon monoxide over silica-supported tantalum oxide
Tanaka, Tsunehiro,Nojima, Hiroyuki,Yamamoto, Takashi,Takenaka, Sakae,Funabiki, Takuzo,Yoshida, Satohiro
, p. 5235 - 5239 (1999)
Tantalum oxide (10 wt.% as Ta2O5) supported on silica was prepared and the structure and the photo-oxidation of carbon monoxide over the catalyst sample were investigated. XAFS analysis showed that surface tantalate is a TaO4 tetrahedral species with a Ta=O bond which is a photoactive center. The initiation of the photo-oxidation of carbon monoxide is the photoadsorption of an oxygen molecule on the catalyst sample, elucidated by photoluminescence. EPR spectroscopy showed that the photo-excited center interacts with an oxygen molecule to form a T-type ozonide ion. A carbon monoxide ion attacks the ozonide ion to form an [O3-CO]- paramagnetic intermediate to lead the production of carbon dioxide.
Catalytic properties of γ-Al2O3 supported Pt-FeOx catalysts for complete oxidation of formaldehyde at ambient temperature
Cui, Weiyi,Yuan, Xiaoling,Wu, Ping,Zheng, Bin,Zhang, Wenxiang,Jia, Mingjun
, p. 104330 - 104336 (2015)
A series of γ-Al2O3 supported Pt-FeOx catalysts (Pt-FeOx/Al2O3) with different Fe/Pt atom ratios were prepared, and their catalytic properties were investigated in the oxidation of formaldehyde. It was found that the catalytic activities of Pt-FeOx/Al2O3 catalysts are varied with the change of Fe/Pt ratios. Among them, the sample with a Fe/Pt ratio of 1.0 exhibits the highest activity, which can efficiently convert formaldehyde to CO2 at ambient temperature. The catalytic activity of the Pt-FeOx/Al2O3 catalyst can be further improved by the addition of water vapor into the feed stream. A variety of characterization results showed that both Pt nanoparticles and FeOx species are highly dispersed on the surface of the γ-Al2O3 support. Changing Fe/Pt ratios could influence the chemical states and the redox properties of Pt and Fe species. The catalysts with appropriate Fe/Pt ratios have more accessible active sites, i.e., the Pt-O-Fe species, which are located at the boundaries between FeOx and Pt nanoparticles, thus showing high activity for the oxidation of formaldehyde under ambient conditions.
Purification and characterization of urease from dehusked pigeonpea (Cajanus cajan L) seeds.
Das, Nilanjana,Kayastha, Arvind M,Srivastava, Punit K
, p. 513 - 521 (2002)
Urease has been purified from the dehusked seeds of pigeonpea (Cajanus cajan L.) to apparent electrophoretic homogeneity with approximately 200 fold purification, with a specific activity of 6.24 x10(3) U mg(-1) protein. The enzyme was purified by the sequence of steps, namely, first acetone fractionation, acid step, a second acetone fractionation followed by gel filtration and anion-exchange chromatographies. Single band was observed in both native- and SDS-PAGE. The molecular mass estimated for the native enzyme was 540 kDa whereas subunit values of 90 kDa were determined. Hence, urease is a hexamer of identical subunits. Nickel was observed in the purified enzyme from atomic absorption spectroscopy with approximately 2 nickel ions per enzyme subunit. Both jack bean and soybean ureases are serologically related to pigeonpea urease. The amino acid composition of pigeonpea urease shows high acidic amino acid content. The N-terminal sequence of pigeonpea urease, determined up to the 20th residue, was homologous to that of jack bean and soybean seed ureases. The optimum pH was 7.3 in the pH range 5.0-8.5. Pigeonpea urease shows K(m) for urea of 3.0+/-0.2 mM in 0.05 M Tris-acetate buffer, pH 7.3, at 37 degrees C. The turnover number, k(cat), was observed to be 6.2 x 10(4) s(-1) and k(cat)/K(m) was 2.1 x 10(7) M(-1) s(-1). Pigeonpea urease shows high specificity for its primary substrate urea.
The effect of the particle size on the kinetics of CO electrooxidation on high surface area Pt catalysts
Arenz, Matthias,Mayrhofer, Karl J. J.,Stamenkovic, Vojislav,Blizanac, Berislav B.,Tomoyuki, Tada,Ross, Phil N.,Markovic, Nenad M.
, p. 6819 - 6829 (2005)
Using high-resolution transmission electron microscopy (TEM), infrared reflection-absorption spectroscopy (IRAS), and electrochemical (EC) measurements, platinum nanoparticles ranging in size from 1 to 30 nm are characterized and their catalytic activity for CO electrooxidation is evaluated. TEM analysis reveals that Pt crystallites are not perfect cubooctahedrons, and that large particles have rougher surfaces than small particles, which have some fairly smooth (111) facets. The importance of defect sites for the catalytic properties of nanoparticles is probed in IRAS experiments by monitoring how the vibrational frequencies of atop CO (νCO) as well as the concomitant development of dissolved CO 2 are affected by the number of defects on the Pt nanoparticles. It is found that defects play a significant role in CO clustering on nanoparticles, causing CO to decrease/increase in local coverage, which yields to anomalous redshift/ blueshift νCO frequency deviations from the normal Stark-tuning behavior. The observed deviations are accompanied by CO2 production, which increases by increasing the number of defects on the nanoparticles, that is, 1 ≤ 2 ad on defect sites rather than by CO energetics. These results are complemented by chronoamperometric and rotating disk electrode (RDE) data. In contrast to CO stripping experiments, we found that in the backsweep of CO bulk oxidation, the activity increases with decreasing particle size, that is, with increasing oxophilicity of the particles.
