A DFT study of molecular adsorption on titania-supported AuRh nanoalloys
Résumé
AuRh/TiO2 nanocatalysts have proved their efficiency in several catalytic reactions. In this work, density functional theory calculations are performed to investigate the effect of the TiO2 support on the structures of fcc 38-atom and 79-atom AuRh nanoalloys and their adsorption properties towards the reactant molecules CO and O-2. d-band centre analysis shows that the d-band model captures the trends better for both larger and supported alloy clusters due to reduced mechanical effects. Calculations reveal metal-to-support electron transfer, depending mainly on which metal atoms lie at the interface with the support. The adsorption strengths of CO and O-2 molecules on experimentally-relevant Janus segregated structures are slightly lower than on pure Rh clusters, which may reduce poisoning effects, while maintaining the high reactivity of Rh. In addition, higher adsorption energies are predicted for the less stable AucoreRhshell structure, which may lead to adsorption-induced restructuring under reaction conditions. (C) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).