State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology , Wuhan, Hubei 430070, China.
Environ Sci Technol. 2014 Aug 19;48(16):9702-8. doi: 10.1021/es5019477. Epub 2014 Jul 24.
Gold (Au) nanoparticles (NPs) supported on well-defined ceria (CeO2) nanorods with exposed {110} and {100} facets were prepared by a deposition-precipitation method and characterized by powder X-ray diffraction, micro-Raman spectroscopy, X-ray photoelectron spectroscopy, nitrogen adsorption-desorption, transmission electron microscopy, high-resolution transmission electron microscopy, and high-angle annular dark-field scanning transmission electron microscopy. Both nanometer and subnanometer gold particles were found to coexist on ceria supports with various Au contents (0.01-5.4 wt %). The catalytic performance of Au/CeO2 catalysts was examined for formaldehyde (HCHO) oxidation into CO2 and H2O at room temperature and shown to be Au content dependent, with 1.8 wt % Au/CeO2 displaying the best performance. On the basis of the results from hydrogen temperature-programmed reduction and in situ Fourier transform infrared spectroscopy observations, the high reactivity and stability of Au/CeO2 catalysts is mainly attributed to the well-defined ceria nanorods with {110} and {100} facets which present a relatively low energy for oxygen vacancy formation. Furthermore, gold NPs could induce the weakened Ce-O bond which in turn promotes HCHO oxidation.
负载在具有暴露的{110}和{100}晶面的高指数晶面 CeO2 纳米棒上的金纳米粒子（Au NPs）通过沉积沉淀法制备，并通过粉末 X 射线衍射、微拉曼光谱、X 射线光电子能谱、氮气吸附-脱附、透射电子显微镜、高分辨率透射电子显微镜和高角环形暗场扫描透射电子显微镜进行了表征。在不同 Au 含量（0.01-5.4wt%）的 CeO2 载体上，发现纳米级和亚纳米级金颗粒共存。Au/CeO2 催化剂用于室温下甲醛（HCHO）氧化为 CO2 和 H2O 的催化性能与 Au 含量有关，1.8wt% Au/CeO2 表现出最佳性能。基于氢气程序升温还原和原位傅里叶变换红外光谱观察的结果，Au/CeO2 催化剂的高反应性和稳定性主要归因于具有{110}和{100}晶面的高指数晶面 CeO2 纳米棒，其具有形成氧空位的相对低能量。此外，金纳米粒子可以诱导减弱的 Ce-O 键，从而促进 HCHO 的氧化。
