Origin of the High Activity of the Ceria-Supported Copper Catalyst for H2O Dissociation

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• 作者：Zongxian Yang ; Luogang Xie ; Dongwei Ma ; Guangtao Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：April 14, 2011
• 年：2011
• 卷：115
• 期：14
• 页码：6730-6740
• 全文大小：1181K
• 年卷期：v.115,no.14(April 14, 2011)
• ISSN：1932-7455

文摘

Ceria-supported copper is a wonderful catalyst for the water鈭抔as shift (WGS) reaction which has been demonstrated experimentally. Using first-principles calculations based on density functional theory (DFT), we identify the mechanisms for the growth of small Cu clusters (Cu_x, x = 1鈭?) on ceria and the dissociation of H₂O on the Cu₄/CeO₂ catalyst. Our calculations indicate that the strong copper鈭抩xygen interaction at the Cu₄/CeO₂ interface is comparable to the copper鈭抍opper intracluster interactions, and the competitions between them determine the morphologies of Cu clusters on ceria. H₂O dissociates with small barriers (0.19鈭?.31 eV) on the Cu₄/CeO₂ catalyst, and the highly catalytic activity originates from the enhanced electrostatic interaction between the positively charged Cu sites and the polar H₂O molecule. The Cu/O interface sites of the ceria-supported copper catalyst are identified as the active sites for H₂O dissociation. As a buffer to accept/release electrons, the ceria support not only activates the Cu sites but also participates in the H₂O dissociation reaction at the Cu/O interface.