Ham, Hyung Chul Stephens, J. Adam Hwang, Gyeong S. Han, Jonghee Nam, Suk Woo Lim, Tae Hoon 2024-01-20T17:02:29Z 2024-01-20T17:02:29Z 2021-09-05 2011-05-16 0920-5861 https://pubs.kist.re.kr/handle/201004/130343 Using density functional theory and cluster expansion-based Monte Carlo simulations, we examine the effect of Pd dispersion on the energetics and barriers for the reaction of O-2 with H atoms to form H2O and H2O2 on a AuPd/Pd(1 1 1) alloy surface. Our calculations show that this hydrogenation reaction is considerably affected by the distribution of Pd and Au atoms in the surface layer. In particular, on isolated Pd monomers surrounded by less active Au atoms, the activation barrier to form H2O2 is appreciably lowered due to the suppression of O-O bond cleavage. In contrast, the reactivity to H2O on the Pd dimer is predicted to be enhanced compared to pure Pd. Using Monte Carlo simulations we also predict Pd ensemble populations in the AuPd surface layer as a function of temperature and composition. Due to the favorability of Au-Pd interactions over Pd-Pd, we find that small ensembles, particularly monomers, preferentially exist. This study highlights how theoretical investigation of bimetallic alloys, particularly the surface arrangement of atoms and the influence of ensembles on reaction energetics, can offer insight into the design of catalysts and tailoring of reaction conditions. (c) 2011 Elsevier B.V. All rights reserved. English ELSEVIER ELECTROCATALYSTS REDUCTION PLATINUM ADSORPTION MONOLAYER ORIGIN GOLD H2O2 Pd ensemble effects on oxygen hydrogenation in AuPd alloys: A combined density functional theory and Monte Carlo study Article 10.1016/j.cattod.2011.02.006 1 CATALYSIS TODAY, v.165, no.1, pp.138 - 144 CATALYSIS TODAY 165 1 138 144 scie scopus 000289789800019 2-s2.0-79955443525 Chemistry, Applied Chemistry, Physical Engineering, Chemical Chemistry Engineering Article ELECTROCATALYSTS REDUCTION PLATINUM ADSORPTION MONOLAYER ORIGIN GOLD H2O2 PdAu alloy catalyst Ensemble effect Oxygen reduction reaction Density functional theory Cluster expansion method Monte Carlo