CeO2分散度对Au／CeO2-SiO2催化剂上甲醛的催化氧化影响

Effect of CeO_2 Dispersion on Catalytic Oxidation of Formaldehyde over Au/CeO_2-SiO_2 Catalysts

采用浸渍法在高比表面积的SiO2上负载不同量的CeO2,得到了CeO2不同颗粒尺寸的CeO2-SiO2载体,并用沉积沉淀法制备了CeO2-SiO2负载的纳米金催化剂。通过元素分析、X射线衍射、程序升温还原、N2物理吸附、拉曼光谱和透射电镜等技术对催化剂进行了表征,并考察了催化甲醛氧化活性。结果表明,高分散度、小尺寸的CeO2有利于得到较小尺寸的Au颗粒,并增强了催化剂的还原能力和氧缺位浓度,从而有利于提高催化剂低温甲醛催化氧化活性。

A series of SiO2 supports with different particle sizes of CeO2 were prepared using an impregnation method, and the CeO2-SiO2 supported gold catalysts were prepared by a deposition-precipitation method. The catalysts were characterized by inductively coupled plasma, X-ray diffraction, temperature-programmed reduction, N2 adsorption, Raman spectroscopy, and transmission electron microscopy techniques.These catalysts were tested for catalytic oxidation of formaldehyde. The results showed that the high dispersion and smaller particle size of CeO2 was beneficial to the formation of small Au particles, the formation of oxygen vacancies and the redox properties of the catalysts, which consequently enhanced the reactivity for low temperature oxidation of formaldehyde.