Ham, Hyung Chul Stephens, J. Adam Hwang, Gyeong S. Han, Jonghee Nam, Suk Woo Lim, Tae Hoon 2024-01-20T15:05:46Z 2024-01-20T15:05:46Z 2021-09-05 2012-03 1948-7185 https://pubs.kist.re.kr/handle/201004/129478 We present a theoretical explanation on how PdAu alloy catalysts can enhance the oxidation of CO molecules based on density functional theory calculations of CO adsorption and oxidation on AuPd/Pd(111) surfaces. Our study suggests that the enhanced activity is largely attributed to the possible existence of "partially-poisoned" Pd ensembles that accommodate fewer CO molecules than Pd atoms. Whereas the oxidation of preadsorbed CO is likely governed by O-2 trapping, our study shows that small Pd ensembles such as dimers and compact trimers tend to provide more active sites than larger ensembles; CO adsorbed on a Pd monomer is found to react hardly with O-2 to form CO2. In addition, we find the tendency of CO-induced Pd agglomeration, which may in turn facilitate CO oxidation by creating more dimers and compact trimers as compared with the adsorbate-free surface where monomers are likely prevailing. English American Chemical Society Role of Small Pd Ensembles in Boosting CO Oxidation in AuPd Alloys Article 10.1021/jz201585q 1 The Journal of Physical Chemistry Letters, v.3, no.5, pp.566 - 570 The Journal of Physical Chemistry Letters 3 5 566 570 N scie scopus 000311188800001 2-s2.0-84857758487 Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Atomic, Molecular & Chemical Chemistry Science & Technology - Other Topics Materials Science Physics Article NEAR-ATMOSPHERIC PRESSURES DENSITY-FUNCTIONAL THEORY SURFACE SEGREGATION ULTRAHIGH-VACUUM ADSORPTION AUPD(100) TOLERANCE CO oxidation PdAu alloy Pd ensembles