Au/TiO2 Catalysts for CO Oxidation: Effect of Gold State to Reactivity

作者：Wei, Shuai; Fu, Xin-Pu; Wang, Wei-Wei; Jin, Zhao^*; Song, Qi-Sheng; Jia, Chun-Jiang^*

来源：Journal of Physical Chemistry C, 2018, 122(9): 4928-4936.

DOI：10.1021/acs.jpcc.7b12418

• METAL-SUPPORT INTERACTIONS
• TIO2 BULK DEFECTS
• CARBON-MONOXIDE
• NANOCRYSTALLINE CEO2
• ROOM-TEMPERATURE
• ACTIVE GOLD
• FT-IR
• AU
• OXYGEN
• ADSORPTION

For decades, it is fairly controversial whether the active gold sites in catalyzing CO oxidation reaction are metallic or positively charged. Herein, catalysts with either metallic or positively charged gold were separately prepared by deposition-precipitation method with the same type of TiO2 matrix. The catalytic behaviors in CO oxidation reaction were observed for two catalysts. For the initially inactive Aun+/TiO2 (1 < n < 3) catalyst, the in situ diffuse-reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) exhibited that CO induced the transformation from Aun+ to Au-0 during reaction. The conversion of gold state resulted in an enhanced CO adsorption ability and further increased the catalytic reactivity. Additionally, the in situ Raman results proved that the formation of Au-0 from Aun+ might be in favor of generating oxygen vacancy in TiO2 matrix, which was beneficial for O-2 activation. Therefore, we reasonably established that the Au-0 was more active than An(n+) in catalyzing the CO oxidation reaction at room temperature.

• 出版日期2018-3-8
• 单位山东大学