jp6b10814_si_001.pdf (1.16 MB)
Origin of Enhanced Activities for CO Oxidation and O2 Reaction over Composition-Optimized Pd50Cu50 Nanoalloy Catalysts
journal contribution
posted on 2016-11-25, 00:00 authored by Wei Zhang, Shiyao Shan, Jin Luo, Adrian Fisher, Jian-Feng Chen, Chuan-Jian Zhong, Jiqin Zhu, Daojian ChengIt
has been shown experimentally that Pd50Cu50 nanoalloy
achieves the maximum activity for CO oxidation (COox)
and oxygen reduction reaction (ORR) on composition-tuned PdCu bimetallic
catalysts, but the origin of this catalytic synergy remains unclear.
In this work, results of our density functional theory (DFT) calculations
show that the weakest adsorption strength of O2 in terms
of the most pronounced charge transfer between Pd and Cu is responsible
for the experimentally observed highest catalytic activity of Pd50Cu50 catalyst for both COox and ORR over a series
of composition-tuned PdCu nanoalloys. For COox, the lowest barrier
energy is attributed to the weakest adsorption strength of O2 on Pd50Cu50 catalyst. In ORR, the lowest barrier
energy for O2 dissociation and also the weakest adsorption
strength of O, OH, and OOH species are related to the weakest adsorption
strength of O2 over the catalyst with a 50:50 ratio of
Pd/Cu. Our work represents the first attempt to address an in-depth
correlation between the theoretical and experimental data on the highly
active PdCu catalysts, the results of which has significant implications
for the design of advanced nanoalloy catalysts with superior catalytic
synergy in terms of the alloy compositions.