Origin of High Activity and Selectivity of PdAu(001) Bimetallic Surfaces toward Vinyl Acetate Synthesis
详细信息 查看全文
- 作者：Dingwang Yuan ; Xingao Gong ; Ruqian Wu
- 刊名：Journal of Physical Chemistry C
- 出版年：2008
- 出版时间：February 7, 2008
- 年：2008
- 卷：112
- 期：5
- 页码：1539 - 1543
- 全文大小：413K
- 年卷期：v.112,no.5(February 7, 2008)
- ISSN：1932-7455
文摘
We perform systematic density functional studies to elucidate the mechanism of vinyl acetate (VA) synthesison Pd/Au(001). Atomic geometries, activation energies, and reaction energies are determined for three separatereaction stages: coupling of ethylene and acetate; 
-H elimination; and VA desorption. Significantly, wefind that the Pd "monomer" pair is much more robust in all three reaction stages than large Pd ensemblessuch as Pd monolayers, mainly due to high mobility of reactants on surrounding Au sites. The remarkablyhigh activity and selectivity of VA reaction on PdAu bimetallic surfaces observed by Goodman et al. areexclusively attributed to the ensemble effects.
-H elimination; and VA desorption. Significantly, wefind that the Pd "monomer" pair is much more robust in all three reaction stages than large Pd ensemblessuch as Pd monolayers, mainly due to high mobility of reactants on surrounding Au sites. The remarkablyhigh activity and selectivity of VA reaction on PdAu bimetallic surfaces observed by Goodman et al. areexclusively attributed to the ensemble effects.