Au/α-Fe_2O_3 催化剂上金活性物种的分析(英文)  

Analysis of the Active Au Species on Au/α-Fe_2O_3 Catalyst

作　　者：尉继英[1] 张振中[1] 张兰[1] 孟弼芳[1] 江锋[1] 

机构地区：[1]清华大学核能与新能源技术研究院北京精细陶瓷重点实验室,北京100084

出　　处：《稀有金属材料与工程》2012年第3期377-382,共6页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(20777046,21077064);Specialized Research Fund for the Doctoral Program of Higher Education of China(20070003027)

摘　　要：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 （2=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 Au^3＋, Au^δ＋ （0〈δ〈1） and Au^0 coexist on the surface of Au/α-Fe2O3 catalysts treated at 110 ℃, and their activity order is Au3＋〉 Aua＋〉 Au~. The sample prepared at pH=8 shows the best catalytic performance since it has more Au^3＋ species and high specific surface area. High temperature calcination can cause serious deactivation due to the reduction of Au^3＋ and Au^δ＋ 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.

关 键 词：Au/α-Fe2O3 一氧化碳低温氧化 活性金物种 失活 

分 类 号：O643.36[理学—物理化学]