resumo
Periodic density functional theory (DFT) calculations have been used to study the effect of doping a gold model surface with atoms of other transition metals on the catalysis of the reaction of oxygen dissociation. It was found that the doping of gold surfaces with atoms of Rh, Ir or Ni stabilizes the adsorbate-surface interactions with a concomitant decrease of the activation energy barriers for the oxygen dissociation to values that are smaller than the adsorption energies of molecular oxygen (O-2*) on those surfaces. These findings suggest that O-2 dissociation is possible at normal conditions on these bimetallic surfaces, which is very relevant not only for the oxidation of CO to CO2 but for other oxidation reactions. In the case of the most active bimetallic surface obtained by doping with Ni atoms, it is shown that the reaction of CO oxidation is more favorable than the reaction of CO dissociation, i.e., suggesting that CO methanation will be less likely. Finally, useful relationships relating the activation energy barrier for the reaction of O-2 dissociation with the Bader charge in the doping element, with the reaction energy, with the adsorption energy of the reaction products and with the adsorption energy of an oxygen atom were obtained. (c) 2013 Elsevier B.V. All rights reserved.
palavras-chave
WATER-GAS SHIFT; AMORPHOUS NI-RU-B/ZRO2 CATALYST; DENSITY-FUNCTIONAL THEORY; TOTAL-ENERGY CALCULATIONS; SELECTIVE CO METHANATION; AUGMENTED-WAVE METHOD; OXYGEN-ADSORPTION; MOLECULAR-OXYGEN; LOW-TEMPERATURE; HYDROGEN-PRODUCTION
categoria
Chemistry; Environmental Sciences & Ecology
autores
Fajin, JLC; Cordeiro, MNDS; Gomes, JRB
nossos autores
José R. B. Gomes
Investigador PrincipalProjectos
Computational Design of new catalysts for the water gas shift reaction (PTDC/QUI-QUI/117439/2010)
agradecimentos
Thanks are due to Fundacao para a Ciencia e Tecnologia (FCT), Lisbon, Portugal and to FEDER for financial support to REQUIMTE and to CICECO, projects PEst-C/EQB/LA0006/2011 and PEst-C/CTM/LA0011/2011, respectively. Thanks are also due to FCT and FEDER for project PTDC/QUI-QUI/117439/2010 (FCOMP-01-0124-FEDER-020977) and for Programa Ciencia 2007. JLCF acknowledges FCT for the grant SFRH/BPD/64566/2009 co-financed by the Fundo Social Europeu (FSE).