Theoretical Study of the Oxidation of Formic Acid on the PtAu(111) Surface in the Continuum Water Solution Phase

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• 作者：Wenhui Zhong ; Rongyue Wang ; Dongju Zhang ; Chengbu Liu
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 15, 2012
• 年：2012
• 卷：116
• 期：45
• 页码：24143-24150
• 全文大小：592K
• 年卷期：v.116,no.45(November 15, 2012)
• ISSN：1932-7455

文摘

By performing density functional theory calculations, we have studied the dual-path mechanism of formic acid (HCOOH) oxidation on the PtAu(111) surface in the continuum water solution phase. The direct pathway involving the dehydrogenation of HCOOH to form CO₂ occurs with a barrier of 15.5 kcal/mol, which is in contrast to the much higher barrier of 99.2 kcal/mol in the indirect pathway involving the dehydration of HCOOH to form a CO intermediate. In comparison, the calculated barriers on the Pt(111) surface in direct and indirect pathways are 5.8 and 32.9 kcal/mol, respectively. The theoretical results emphasize that a bimetallic PtAu(111) surface significantly increases the barrier difference between the two pathways to 83.7 kcal/mol from 27.1 kcal/mol on the Pt(111) surface and thus can hinder remarkably the indirect pathway. The theoretical results rationalize well the experimental finding that bimetallic PtAu catalysts show higher catalytic activity toward HCOOH oxidation than pure Pt catalysts.