resumo
The NO dissociation on a series of doped gold surfaces (type TMn@Au(111) or TMn@Au(110), with TMn = Ni, Ir, Rh, or Ag and referring n to the number of dopant atoms per unit cell) was investigated through periodic density functional theory calculations. Generally, doping of Au(111) and Au(110) matrices was found to strengthen the interaction with NO species, with the exception of Ag, and was found to increase the energy barrier for dissociation, with the exception of Ni on Au(111). The calculations suggest that the NO dissociation is only possible in the case of the Ir@Au(110) bimetallic surface but only at high temperatures. The increase of the contents of Ir on Au(110) was found to improve significantly the catalytic activity of gold towards the NO dissociation (E-act = similar to 1 eV). Nevertheless, this energy barrier is almost the double of that calculated for NO dissociation on pure Ir(110). However, mixing the two most interesting dopant atoms resulted in a catalyst model of the type Ir@Ni(110) that was found to decrease the energy barrier to values close to those calculated for pure Ir surfaces, i.e., similar to 0.4 eV, and at the same time the dissociation reaction became mildly exothermic. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790602]
palavras-chave
SELECTIVE CATALYTIC-REDUCTION; TOTAL-ENERGY CALCULATIONS; AUGMENTED-WAVE METHOD; NITRIC-OXIDE; DIRECT DECOMPOSITION; AUTOMOTIVE EXHAUST; STORAGE-REDUCTION; CARBON-MONOXIDE; LOW-TEMPERATURE; CO REACTION
categoria
Chemistry; Physics
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 co-financed by Programa COMPETE. J.L.C.F. acknowledges FCT for the Grant No. SFRH/BPD/64566/2009 co-financed by the Fundo Social Europeu (FSE).