Correlation between the Oxidation State of Copper and the Photocatalytic Activity of Cu/Nb2O5

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• 作者：Shinya Furukawa ; Daisuke Tsukio ; Tetsuya Shishido ; Kentaro Teramura ; Tsunehiro Tanaka
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：June 7, 2012
• 年：2012
• 卷：116
• 期：22
• 页码：12181-12186
• 全文大小：354K
• 年卷期：v.116,no.22(June 7, 2012)
• ISSN：1932-7455

文摘

A structural analysis of the reduction鈥搊xidation process of copper loaded on Cu/Nb₂O₅ has been performed using Cu K-edge XAFS spectroscopy to reveal the correlation between the oxidation state of copper and the catalytic activity of alcohol photooxidation. On the basis of the simulation of the XANES spectra of Cu/Nb₂O₅, the superposition of Cu metal (Cu(0)), Cu₂O (Cu(I)), and CuO (Cu(II)) is observed, and, furthermore, the concentration of these three phases was evaluated. XANES and EXAFS analyses revealed the following reduction鈥搊xidation process. Cu metal particles with a diameter of approximately 4 nm were formed after reductions at 673 K. Cu₂O and CuO phases were formed in the surface layers at low oxidation temperature. The process of formation was followed by phase growth both in the surface layers and in the bulk Cu particle with increasing oxidation temperature. The change in photocatalytic activity well correlated with the fraction of Cu₂O (Cu(I)).