National Natural Science Foundation of China (20777046, 21077064); Specialized Research Fund for the Doctoral Program of Higher Education of China (20070003027)
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采用沉积沉淀法制备了CO低温氧化Au/α-Fe2O3催化剂，利用X射线衍射（XRD）、X射线光电子能谱（XPS）、BET比表面测定、程序升温还原（H2-TPR）等表征技术，对比了制备过程pH值的微小变化、焙烧及光线照射对催化剂结构及催化性能的影响，探明了Au/α-Fe2O3催化剂的活性物种。结果表明，110 ℃处理的Au/α-Fe2O3催化剂表面同时存在Au3+、Au0以及过渡态Auδ+（0<δ<1），它们对CO氧化的活性顺序为Au3+>Auδ+>Au0；pH值为8条件下制备的催化剂Au3+含量高、比表面积大，催化性能最好；高温焙烧使氧化态金还原的同时也使载体比表面积严重缩小，催化活性显著下降；紫外线照射可以引起Au3+的逐渐还原以及Au0颗粒的生长，其催化失活作用弱于高温焙烧。
Au/α-Fe2O3 catalysts for CO oxidation were prepared by chemical coprecipitation at different pH values, and the as-prepared samples were calcined or UV (λ=254 nm) irradiated, respectively. The structure was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption and desorption analysis (BET) and temperature programmed reduction (H2-TPR), and the active Au species on the catalysts was investigated. The results show that Au3+, Auδ+（0≤δ≤1）and Au0 coexist on the surface of Au/α-Fe2O3 catalysts treated at 110 °C, and their activity order is Au3+> Auδ+> Au0. The sample prepared at pH=8 shows the best catalytic performance since it has more Au3+ species and high specific surface area. High temperature calcination can cause serious deactivation due to the reduction of Au3+ and Auδ+ species, together with the decrease of the specific surface area of α-Fe2O3. UV irradiation can also cause the reduction of oxidative Au species and the growth of Au particle.
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尉继英,张振中,张 兰,孟弼芳,江 锋. Analysis of the Active Au Species on Au/α-Fe2O3 Catalyst[J].稀有金属材料与工程,2012,41(3):377~382.[Wei Jiying, Zhang Zhenzhong, Zhang Lan, Meng Bifang, Jiang Feng. Analysis of the Active Au Species on Au/α-Fe2O3 Catalyst[J]. Rare Metal Materials and Engineering,2012,41(3):377~382.]
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- 收稿日期:2011-11-30