نتایج جستجو برای: cu based catalyst
تعداد نتایج: 3021400 فیلتر نتایج به سال:
Using a combination of complementary in situ X-ray photoelectron spectroscopy and X-ray diffraction, we study the fundamental mechanisms underlying the chemical vapor deposition (CVD) of hexagonal boron nitride (h-BN) on polycrystalline Cu. The nucleation and growth of h-BN layers is found to occur isothermally, i.e., at constant elevated temperature, on the Cu surface during exposure to borazi...
Zincian georgeite, an amorphous copper-zinc hydroxycarbonate, has been prepared by co-precipitation using acetate salts and ammonium carbonate. Incorporation of zinc into the georgeite phase and mild ageing conditions inhibits crystallisation into zincian malachite or aurichalcite. This zincian georgeite precursor was used to prepare a Cu/ZnO catalyst, which exhibits a superior performance to a...
We report here a Cu(0)-based catalyst free of noble metals for the electrocatalytic hydrogen evolution reaction in neutral water with an onset overpotential of only 70 mV. This is the lowest reported value among Cu(0)-based catalysts for the hydrogen evolution reaction in neutral water.
Synthesis of dimethyl carbonate (DMC) from CO2 and methanol under milder reaction conditions was performed using reduced cerium oxide catalysts and reduced copper-promoted Ce oxide catalysts. Although the conversion of methanol was low (0.005-0.11%) for 2 h of reaction, DMC was synthesized as low as 353 K and at total pressure of as low as 1.3 MPa using reduced Cu-CeO2 catalyst (0.5 wt% of Cu)....
methanol steam reforming plays a pivotal role to produce hydrogen for fuel cell systems in a low temperature range. to accomplish higher methanol conversion and lower co production, the reaction was catalyzed by cuznfe mixed oxides. various ratios of fe and cu/zn were coprecipitated in differential method to optimize the cuznfe structure. the sample containing 45cu50zn5fe (wt. %) revealed its m...
In the present work, a microchannel reactor for autothermal reforming of methanol using a synthesized catalyst porous alumina support-CuO/ZnO mixed with ZrO₂ sol washcoat has been developed and its fine structure and inner surface characterized. Experimentally, CuO/ZnO and alumina support with ZrO₂ sol washcoat catalyst (catalyst slurries) nanoparticles is the catalytically active component of ...
The direct synthesis process of dimethyl ether (DME) from syngas in slurry reactors is considered to be promising because of its advantages in caloric transfer. In this paper, the influences of operating conditions (temperature, pressure and weight hourly space velocity) on the conversion of CO, selectivity of DME and methanol were studied in a stirred autoclave over Cu-Zn-Al-Zr slurry catalyst...
Atom transfer radical addition (ATRA) and polymerisation (ATRP) reactions are commonly catalyzed by copper(I) complexes which react, reversibly, with a dormant alkyl halide initiator (RX) releasing a reactive organic radical R˙. The copper catalyst bears a multidentate N-donor ligand (L) and the active catalyst is simply Cu(I)L. The role of the catalyst in these reactions is to abstract a halog...
The activity and recyclability of Cu-MOF-74 as a catalyst was studied for the ligand-free C-O cross-coupling reaction of 4-nitrobenzaldehyde (NB) with phenol (Ph) to form 4-formyldiphenyl ether (FDE). Cu-MOF-74 is characterized by having unsaturated copper sites in a highly porous metal-organic framework. The influence of solvent, reaction temperature, NB/Ph ratio, catalyst concentration, and b...
The effect of Cu on the reduction behavior and surface properties of supported and unsupported Fe-based Fischer-Tropsch synthesis (FTS) catalysts was investigated using in situ X-ray photoelectron spectroscopy (XPS) and in situ X-ray absorption spectroscopy (XAS) in combination with ex situ bulk characterization. During exposure to 0.4 mbar CO-H(2) above 180 degrees C, the reduction of CuO to C...
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