Unexpected Size Effect Observed in ZnO-Au Composite Photocatalysts

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• 作者：Noh Soo Han ; Dukhan Kim ; Jong Woon Lee ; Jaehyun Kim ; Hyeong Seop Shim ; Yongjin Lee ; Dongil Lee ; Jae Kyu Song
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 20, 2016
• 年：2016
• 卷：8
• 期：2
• 页码：1067-1072
• 全文大小：357K
• ISSN：1944-8252

文摘

Semiconductor-metal nanocomposites prepared with well-defined gold nanoclusters, such as Au₂₅, Au₁₄₄, and Au₈₀₇, showed size-dependent photocatalytic activities for the reduction of nile blue and azobenzene. Whereas the photoreduction of nile blue was directly related with the charge separation and transfer rate from the photoexcited ZnO to gold nanoclusters, the photoreaction of azobenzene showed unexpected size effect with a clear threshold. Mechanistic investigations revealed that the photoreduction of azobenzene proceeded via a proton-coupled electron transfer process. The photocatalytic activity of the ZnO-Au nanocomposites was also dependent on the excitation intensity, demonstrating that the multielectron/multiproton process was controlled by the charge separation and transfer in the nanocomposites.