نتایج جستجو برای: catalyst surface reaction

تعداد نتایج: 1046577  

Journal: :Physical chemistry chemical physics : PCCP 2014
Niels Bendtsen Halck Valery Petrykin Petr Krtil Jan Rossmeisl

Oxygen evolution catalysis is restricted by the interdependence of adsorption energies of the reaction intermediates and the surface reactivity. The interdependence reduces the number of degrees of freedom available for catalyst optimization. Here it is demonstrated that this limitation can be removed by active site modification. This can be achieved on ruthenia by incorporation of Ni or Co int...

Journal: :Journal of physics. Condensed matter : an Institute of Physics journal 2009
Sean M McClure M Lundwall F Yang Z Zhou D W Goodman

Rh/SiO(2) model catalyst surfaces are prepared under ultra-high vacuum conditions and examined in situ using scanning tunneling microscope and CO infrared reflection absorption techniques, to quantify the number and kinds of active Rh surface sites available for kinetic reaction (CO oxidation) as a function of Rh particle size. The results are compared against CO desorption measurements and ele...

Journal: :Nature nanotechnology 2008
Carolina Novo Alison M Funston Paul Mulvaney

Heterogeneous catalysts have been pivotal to the development of the modern chemical industry and are essential for catalysing many industrial reactions. However, reaction rates are different for every individual catalyst particle and depend upon each particle's morphology and size, crystal structure and composition. Measuring the rates of reaction on single nanocrystals will enable the role of ...

2014
Younes Abrouki Abdelkader Anouzla Hayat Loukili Jamal Bennazha Rabiaâ Lotfi Ahmed Rayadh My Abdellah Bahlaoui Saïd Sebti Driss Zakarya Mohamed Zahouily

A simple protocol for the efficient preparation of β-mercapto carbonyl derivatives as antimycobacterial drugs has been achieved via Thia-Michael reaction between chalcones derivatives and thiols in the presence of calcium pyrophosphate as a heterogeneous catalyst under mild reaction conditions. The central composite design was used to design an experimental program to provide data to model the ...

Journal: :Faraday discussions 2016
Alastair R McInroy John M Winfield Chris C Dudman Peter Jones David Lennon

In previous work by the authors, aspects of the surface chemistry connected with methyl chloride synthesis over an η-alumina catalyst have been examined. This communication considers a role for Group 1 metal salts to modify the catalytic performance of the well characterised η-alumina catalyst. Firstly, based on a previously postulated mechanism for the reaction of methanol on η-alumina, a mech...

Journal: :Angewandte Chemie 2015
Carlos G Morales-Guio Laurent Liardet Matthew T Mayer S David Tilley Michael Grätzel Xile Hu

The splitting of water into hydrogen and oxygen molecules using sunlight is an attractive method for solar energy storage. Until now, photoelectrochemical hydrogen evolution is mostly studied in acidic solutions, in which the hydrogen evolution is more facile than in alkaline solutions. Herein, we report photoelectrochemical hydrogen production in alkaline solutions, which are more favorable th...

Journal: :The Journal of chemical physics 2015
J-H Franke D S Kosov

We study the adsorption and ring-opening of lactide on the naturally chiral metal surface Pt(321)(S). Lactide is a precursor for polylactic acid ring-opening polymerization, and Pt is a well known catalyst surface. We study, here, the energetics of the ring-opening of lactide on a surface that has a high density of kink atoms. These sites are expected to be present on a realistic Pt surface and...

2009
S. Rodrigues L. C. A. Mazzone F. F. P. Santos M. G. A. Cruz F. A. N. Fernandes

Biodiesel is a renewable liquid fuel that can be produced by a transesterification reaction between a vegetable oil and an alcohol. This paper evaluates and optimizes the production of ethyl esters (biodiesel) from soybean oil and ethanol. The reaction was carried out by applying ultrasound under atmospheric pressure and ambient temperature. Response surface methodology was used to evaluate the...

Journal: :Science 2007
Thomas F Jaramillo Kristina P Jørgensen Jacob Bonde Jane H Nielsen Sebastian Horch Ib Chorkendorff

The identification of the active sites in heterogeneous catalysis requires a combination of surface sensitive methods and reactivity studies. We determined the active site for hydrogen evolution, a reaction catalyzed by precious metals, on nanoparticulate molybdenum disulfide (MoS2) by atomically resolving the surface of this catalyst before measuring electrochemical activity in solution. By pr...

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