Carbon Monoxide Oxidation by Polyoxometalate‐Supported Gold Nanoparticulate Catalysts: Activity,Stability, and Temperature‐ Dependent Activation Properties |
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| Authors: | Dr Takuya Yoshida Prof?Dr Toru Murayama Prof?Dr Norihito Sakaguchi Prof?Dr Mitsutaka Okumura Prof?Dr Tamao Ishida Prof?Dr Masatake Haruta |
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| Institution: | 1. Research Center for Gold Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, Tokyo, Japan;2. Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Sapporo, Japan;3. Department of Chemistry, Graduate School of Science, Osaka University, Osaka, Japan |
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| Abstract: | Nanoparticulate gold supported on a Keggin‐type polyoxometalate (POM), Cs4α‐SiW12O40]?n H2O, was prepared by the sol immobilization method. The size of the gold nanoparticles (NPs) was approximately 2 nm, which was almost the same as the size of the gold colloid precursor. Deposition of gold NPs smaller than 2 nm onto POM (Au/POM) was essential for a high catalytic activity for CO oxidation. The temperature for 50 % CO conversion was ?67 °C. The catalyst showed extremely high stability for at least one month at 0 °C with full conversion. The catalytic activity and the reaction mechanism drastically changed at temperatures higher than 40 °C, showing a unique behavior called a U‐shaped curve. It was revealed by IR measurement that Auδ+ was a CO adsorption site and that adsorbed water promoted CO oxidation for the Au/POM catalyst. This is the first report on CO oxidation utilizing Au/POMs catalysts, and there is a potential for expansion to various gas‐phase reactions. |
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| Keywords: | gold heterogeneous catalysis nanoparticles oxidation polyoxometalates |
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