resumo
General trends for the reaction of water dissociation on some selected transition metal (TM) bimetallic surfaces of the type TM1@TM2(111) or TM1@ TM2(110), with TM1= Ag, Ni, Rh, or Ir and TM2 = Cu, Au, Ni, or Ir, are interpreted from periodic density functional theory calculations. It was found that the water dissociation on bimetallic surfaces follows relationships that link the activation energy barrier with the reaction energy or with the adsorption energy of the reaction products. Furthermore, it was also found that the doping of metallic surfaces with atoms of other metals leads to a stabilizing cooperative effect of both in the adsorption of water, its dissociation products, and transition state configuration. Importantly, the catalytic activity of the bimetallic systems is found to increase visibly when compared with the reactivity of the pure parent surfaces. In fact, the activation barriers calculated for water dissociation on some bimetallic surfaces are significantly lowered when compared with the activation energies for the reaction of water dissociation on pure surfaces of the parent metals.
palavras-chave
GAS SHIFT REACTION; DENSITY-FUNCTIONAL THEORY; TOTAL-ENERGY CALCULATIONS; AUGMENTED-WAVE METHOD; SUPPORTED CU; BASIS-SET; CATALYSTS; METAL; ADSORPTION; AU
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
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, Programme Ciencia 2007, and to FEDER for financial support to REQUIMTE and to CICECO (Pest-C/EQB/LA0006/2011 and Pest-C/CTM/LA0011/2011). This work has been supported by FCT through project PTDC/QUI-QUI/117439/2010 cofinanced by Programa COMPETE. J.L.C.F. acknowledges FCT for the grant SFRH/BPD/64566/2009 cofinanced by the Fundo Social Europeu (FSE).