Site-Dependent Activity and Selectivity of H2O2 Formation from H2 and O2 over Au-Based Catalysts
Site-Dependent Activity and Selectivity of H2O2 Formation from H2 and O2 over Au-Based Catalysts
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DOI：
10.1021/acs.iecr.9b01459
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发表时间：
2019-08
影响因子：
4.2
通讯作者：
Yan Tang;Zhihua Zhang;Mengke Lu;Bingxu Chen;Wenzhao Fu;J. Gan;G. Qian;Xuezhi Duan;Xinggui Zhou
中科院分区：
文献类型：
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作者：
Yan Tang;Zhihua Zhang;Mengke Lu;Bingxu Chen;Wenzhao Fu;J. Gan;G. Qian;Xuezhi Duan;Xinggui Zhou
对Au催化H ↓ [2]与O ↓ [2]反应生成H ↓ [2] O ↓ [2]的结构敏感性的基本认识具有重要的科学和工业意义。本文采用密度泛函理论（DFT）计算揭示了三种典型的Au（111）、Au（100）和Au（211）晶位上H + O+形成活性和选择性随晶位的变化规律.氢解离被认为是速率控制步骤。结构和电荷分析以及能垒分解表明，Au（211）上的一个低配位的边缘原子是氢解离的活性中心。此外，氢化/脱附的物种涉及的O-O键和它们的裂解之间的竞争反应进行了比较研究。发现Au（111）对H ↓ [2] O ↓ [3]具有最高的选择性。最后，低配位的Au原子与Au（111）的结合被认为是H ↓ [2] O ↓ [3]形成的催化活性中心。这些结果对制备高活性、高选择性的H_2O生成催化剂具有重要的参考价值。
Fundamental understanding of the structure sensitivity of Au-catalyzed H₂O₂ formation from H₂ with O₂ is of prime scientific and industrial significance. Herein, DFT calculations are employed to reveal the underling nature of the site-dependent H₂O₂ formation activity and selectivity over three typical Au(111), Au(100), and Au(211) sites. The hydrogen dissociation is suggested as the rate-determining step. The structural and charge analysis and the energy barrier decomposition indicate one lower-coordinated edge atom on the Au(211) as the active site for hydrogen dissociation. Furthermore, competition reactions between hydrogenation/desorption of the species involving the O–O bonds and their cleavage are comparatively studied. Au(111) is found to exhibit the highest selectivity to H₂O₂. Finally, a combination of the low-coordinated Au atom with Au(111) is proposed as the catalytically active center of H₂O₂ formation. The results demonstrated here could be valuable for fabricating highly active and selective catalysts for H₂O₂ formation.