Strong Metal鈥揝upport Interactions between Gold Nanoparticles and ZnO Nanorods in CO Oxidation

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• 作者：Xiaoyan Liu ; Ming-Han Liu ; Yi-Chia Luo ; Chung-Yuan Mou ; Shawn D. Lin ; Hongkui Cheng ; Jin-Ming Chen ; Jyh-Fu Lee ; Tien-Sung Lin
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：June 20, 2012
• 年：2012
• 卷：134
• 期：24
• 页码：10251-10258
• 全文大小：485K
• 年卷期：v.134,no.24(June 20, 2012)
• ISSN：1520-5126

文摘

The catalytic performances of supported gold nanoparticles depend critically on the nature of support. Here, we report the first evidence of strong metal鈥搒upport interactions (SMSI) between gold nanoparticles and ZnO nanorods based on results of structural and spectroscopic characterization. The catalyst shows encapsulation of gold nanoparticles by ZnO and the electron transfer between gold and the support. Detailed characterizations of the interaction between Au nanoparticles and ZnO were done with transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR), and FTIR study of adsorbed CO. The significance of the SMSI effect is further investigated by probing the efficiency of CO oxidation over the Au/ZnO-nanorod. In contrast to the classical reductive SMSI in the TiO₂ supported group VIII metals which appears after high temperature reduction in H₂ with electron transfer from the support to metals, the oxidative SMSI in Au/ZnO-nanorod system gives oxygen-induced burial and electron transfer from gold to support. In CO oxidation, we found that the oxidative SMSI state is associated with positively charged gold nanoparticles with strong effect on its catalytic activity before and after encapsulation. The oxidative SMSI can be reversed by hydrogen treatment to induce AuZn alloy formation, de-encapsulation, and electron transfer from support to Au. Our discovery of the SMSI effects in Au/ZnO nanorods gives new understandings of the interaction between gold and support and provides new way to control the interaction between gold and the support as well as catalytic activity.