نتایج جستجو برای: monometallic catalyst
تعداد نتایج: 44338 فیلتر نتایج به سال:
We present a detailed study of the mechanism for oxidative heteroarylation, based on DFT calculations and experimental observations. We propose binuclear Au(II)-Au(II) complexes to be key intermediates in the mechanism for gold catalyzed oxidative heteroarylation. The reaction is thought to proceed via a gold redox cycle involving initial oxidation of Au(I) to binuclear Au(II)-Au(II) complexes ...
A series of iridacycles bearing π-bonded moieties of variable electron-withdrawing capabilities were tested for their ability to promote water oxidation catalysis (WOC) in the presence of high loading in a sacrificial oxidant, under conditions chosen for optimal dioxygen production. This report shows that none of these complexes performs differently than monometallic iridacycles and that the π-...
in this research carbon nanotubes were produced by chemical vapor deposition of acetylene over a mixture of iron and cobalt catalysts supported on nanometric tio2 and the influences of two synthesis parameters: growth temperature and catalyst composition ratio on properties of end-product carbon nanotubes were investigated. the catalytic basis was prepared by wet impregnation method with differ...
CO2 methanation was studied over monometallic catalyst, i.e., Ni, Fe and Co; on CeO2-Cr2O3 support. The catalysts were prepared using one-pot hydrolysis of mixed metal nitrates ammonium carbonate. Physicochemical properties the pre- post-exposure characterized by X-Ray Powder Diffraction (XRD), Hydrogen Temperature Programmed Reduction (H2-TPR), Field Emission Scanning Electron Microscope (FE-S...
Cooperative bimetallic catalysis has been documented in several recently reported asymmetric epoxide opening reactions that display second-order kinetic dependence on catalyst, specific requirements for multiple metal ions, and/or pronounced catalyst nonlinear effects.1 In such systems, one metal is proposed to serve as Lewis acid for epoxide activation and another as counterion for the nucleop...
Bimetallic Ni-Cu/SiO2 catalysts with different Cu loading (2–5 wt%) were developed for liquid phase selective hydrogenation of furfural to furfuryl alcohol. Among these, bimetallic 2%Ni-X%Cu/SiO2 (X = 2, 5) exhibited better catalytic performances than monometallic 2%Ni/SiO2 and 2%Cu/SiO2. Moreover, the 2%Ni-5%Cu/SiO2 catalyst showed best performance 94% conversion 64% alcohol selectivity. The s...
Highly active and stable bimetallic Au-Pd catalysts have been extensively studied for several liquid-phase oxidation reactions in recent years, but there are far fewer reports on the use of these catalysts for low-temperature gas-phase reactions. Here we initially established the presence of a synergistic effect in a range of bimetallic Au-Pd/CeZrO4 catalysts, by measuring their activity for se...
Nitrate (NO3(-)) and nitrite (NO2(-)) anions are often found in groundwater and surface water as contaminants globally, especially in agricultural areas due to nitrate-rich fertilizer use. One popular approach to studying the removal of nitrite/nitrate from water has been their degradation to dinitrogen via Pd-based reduction catalysis. However, little progress has been made towards understandi...
It has been found that the bimetallic nanoclusters often have so-called core/shell structure if they are prepared by alcohol-reduction of two kinds of noble metal ions in the presence of a water-soluble polymer like poly(N-vinyl-2-pyrolidone)(PVP), and that the core/ shell structured bimetallic nanoclusters have much higher catalytic activity than the corresponding monometallic nanoclusters. He...
Bimetallic Pd-Au and Pt-Au and monometallic Pd, Pt, and Au films were prepared by physical vapor deposition. The resulting surfaces were characterized by means of XPS, AFM, and CO adsorption from the liquid phase (CH2Cl2) monitored by ATR-IR spectroscopy. CO adsorption combined with ATR-IR proved to be a very sensitive method for probing the degree of interdiffusion occurring at the interfaces ...
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