氧化锆晶型对负载钨催化剂结构和表面酸性的影响

The Structure and Surface Acidity of Tungsten Oxide Supported on the Zirconium Oxides

运用BET、XRD、FT -Raman以及微量吸附量热手段对 3种ZrO2 及其前体Zr(OH) 4上负载钨催化剂进行表征 结果表明 :原料和制备条件对ZrO2 的结构有显著影响 钨物种可使浸渍在其上的Zr (OH ) 4转变为四方晶型ZrO2 ;但较难使浸渍在其上的ZrO2 发生晶型转变 该催化剂表面酸位的形成不仅与ZrO2 的晶型有关 ,也与表面WOx 以及WOx 与ZrO2 的协同作用有关 催化剂上强酸位可因残留的Na+ 离子所毒化阻抑 ,但少量Y3 +

The structure and surface acidity of zirconia supported tungsten oxide are studied by using BET, XRD, FT Raman, Tian-calvet microcalorimetry. The starting material and the different preparing conditions are able to affect considerably the final ZrO 2 structure. The zirconium hydroxide supported tungsten species will promote the transformation of different kinds of hydroxides into tetragonal system ZrO 2. Generation of strong acidic sites will be dependent on the crystal structure of ZrO 2 phase, the type of tungsten oxide species WOx and the cooperation betwween the surface tungsten oxide WOx and overlayer ZrO 2. Remaining sodium ion impurities can prohibit creation of strong acidic sites or directly poison these sites, introduce of yttrium component into zirconium oxide, howerer, has not shown appreciable effect on the surface acidity.