Theoretical Study of the Direct Synthesis of H2O2 on Pd and Pd/Au Surfaces
Theoretical Study of the Direct Synthesis of H2O2 on Pd and Pd/Au Surfaces
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DOI：
10.1021/jp803021n
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发表时间：
2008-11
影响因子：
3.7
通讯作者：
A. Staykov;T. Kamachi;T. Ishihara;K. Yoshizawa
中科院分区：
文献类型：
--
作者：
A. Staykov;T. Kamachi;T. Ishihara;K. Yoshizawa
用周期二维表面第一原理密度泛函方法研究了Pd和Pd/Au催化剂上过氧化氢的直接合成反应。提出了一种从Pd表面氧分子的超氧前驱态开始，再与相邻三重位置上的两个氢原子发生反应的两步反应机理。发现了氧的竞争解离反应导致水的非选择性生成。我们已经证明，表面金原子的存在阻止了这种解离，并增加了对主要产物过氧化氢的选择性，这解释了实验报告的数据。
The direct synthesis of hydrogen peroxide on Pd and Pd/Au catalysts was investigated with first-principle DFT methods for periodic two-dimensional surfaces. A two-step reaction mechanism was proposed starting from a superoxo precursor state of the dioxygen molecule on Pd surface and its subsequent reaction with two hydrogen atoms situated over neighboring 3-fold positions. A competitive reaction of dioxygen dissociation leading to the nonselective formation of water was found. We have shown that the presence of surface gold atoms blocks this dissociation and increases the selectivity toward the main product, H2O2, which explains the experimentally reported data.