Research Center for Gold Chemistry, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo, 192-0397, Japan.
Center for Advanced Research of Energy and Materials, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kitaku, Sapporo, 060-8628, Japan.
Angew Chem Int Ed Engl. 2018 Feb 5;57(6):1523-1527. doi: 10.1002/anie.201710424. Epub 2018 Jan 15.
Nanoparticulate gold supported on a Keggin-type polyoxometalate (POM), Cs [α-SiW O ]⋅n H O, 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 Au 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.
负载在 Keggin 型多金属氧酸盐（POM）Cs[α-SiW12O40]·nH2O 上的纳米金颗粒由溶胶固定化法制备。金纳米颗粒（NPs）的尺寸约为 2nm，几乎与金胶体前体的尺寸相同。将小于 2nm 的金 NPs 沉积到 POM（Au/POM）上对于 CO 氧化的高催化活性是必不可少的。50%CO 转化率的温度为-67°C。该催化剂在 0°C 下至少一个月内具有完全转化率，表现出极高的稳定性。在高于 40°C 的温度下，催化活性和反应机制发生了剧烈变化，表现出一种独特的 U 型曲线行为。IR 测量表明，Au 是 CO 的吸附位，吸附水促进了 Au/POM 催化剂的 CO 氧化。这是利用 Au/POMs 催化剂进行 CO 氧化的首次报道，有望扩展到各种气相反应。
