Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
J Hazard Mater. 2012 Jul 30;225-226:146-54. doi: 10.1016/j.jhazmat.2012.05.011. Epub 2012 May 9.
A series of Pt/Al(2)O(3) catalysts with various tungsten oxide loadings were prepared by a stepwise wet impregnation method. The catalysts were characterized by X-ray diffraction, nitrogen physisorption, Raman, UV-vis diffuse reflectance, transmission electron microscopy and infrared spectroscopy of adsorbed probe molecules (CO, NH(3) or C(3)H(8)). The propane oxidation activity of Pt/Al(2)O(3) catalyst is significantly improved by the addition of tungsten oxide. The tungsten oxide overlayer is presented as monomeric/polymeric WO(x) clusters and WO(3) crystals depending on the loading amount. The most active catalyst occurs at an intermediate surface tungsten density corresponding to the maximum of polytungstate species. The electronic interactions between Pt and WO(x) clusters lead to the generation of more reducible Pt(δ+) species which are suggested to be active sites for propane oxidation. Basically, a simple model is proposed involving the initial CH bond activation at the platinum-tungsten oxide interface.
采用分步浸渍法制备了一系列不同氧化钨负载量的 Pt/Al2O3 催化剂。采用 X 射线衍射、氮物理吸附、拉曼、紫外-可见漫反射、吸附探针分子（CO、NH3 或 C3H8）的透射电子显微镜和红外光谱对催化剂进行了表征。氧化钨的加入显著提高了 Pt/Al2O3 催化剂的丙烷氧化活性。氧化钨覆盖层呈现为单体/聚合 WO(x) 簇和 WO3 晶体，这取决于负载量。在中间表面钨密度下，出现了最活跃的催化剂，对应于多钨酸盐物种的最大值。Pt 和 WO(x) 簇之间的电子相互作用导致更多可还原的 Pt(δ+)物种的生成，这些物种被认为是丙烷氧化的活性位。基本上，提出了一个简单的模型，涉及在铂-氧化钨界面处初始 CH 键的活化。
