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Catalytic Role of Gold in Gold-Based Catalysts: A Density Functional Theory Study on the CO Oxidation on Gold
 

Summary: Catalytic Role of Gold in Gold-Based Catalysts: A Density
Functional Theory Study on the CO Oxidation on Gold
Zhi-Pan Liu and P. Hu*
Contribution from the School of Chemistry, The Queen's UniVersity of Belfast,
Belfast, BT9 5AG, UK
Ali Alavi
Department of Chemistry, UniVersity of Cambridge, CB2 1EW, United Kingdom
Received April 24, 2002
Abstract: Gold-based catalysts have been of intense interests in recent years, being regarded as a new
generation of catalysts due to their unusually high catalytic performance. For example, CO oxidation on
Au/TiO2 has been found to occur at a temperature as low as 200 K. Despite extensive studies in the field,
the microscopic mechanism of CO oxidation on Au-based catalysts remains controversial. Aiming to provide
insight into the catalytic roles of Au, we have performed extensive density functional theory calculations for
the elementary steps in CO oxidation on Au surfaces. O atom adsorption, CO adsorption, O2 dissociation,
and CO oxidation on a series of Au surfaces, including flat surfaces, defects and small clusters, have been
investigated in detail. Many transition states involved are located, and the lowest energy pathways are
determined. We find the following: (i) the most stable site for O atom on Au is the bridge site of step edge,
not a kink site; (ii) O2 dissociation on Au (O2f2Oad) is hindered by high barriers with the lowest barrier
being 0.93 eV on a step edge; (iii) CO can react with atomic O with a substantially lower barrier, 0.25 eV,
on Au steps where CO can adsorb; (iv) CO can react with molecular O2 on Au steps with a low barrier of

  

Source: Alavi, Ali - Department of Chemistry, University of Cambridge

 

Collections: Chemistry