Direct oxidation of propylene to propylene oxide was carried out over Ag-(Mo-W)/ZrO₂ (pH X) catalysts prepared by changing the pH of Zr precursor solution from 3 to 14 while preparing the ZrO₂ support. It was found that the fraction of monoclinic phase and the ratio of acidity to basicity in the catalysts showed a volcano-shaped trend with respect to pH of Zr precursor solution. Such characteristics were well correlated with the selectivity of reaction towards propylene oxide. Ag-(Mo-W)/ZrO₂ (pH 10) with the highest fraction of monoclinic phase of ZrO₂ and ratio of surface acidity to basicity showed the highest selectivity (68%) for propylene oxide.

在Ag-（Mo-W）/ ZrO ₂（pH X）催化剂上将丙烯直接氧化为环氧丙烷，该催化剂是通过在制备ZrO ₂载体的同时将Zr前体溶液的pH从3改变为14而制得的。发现相对于Zr前体溶液的pH，催化剂中的单斜晶相的分数和酸度与碱度的比率显示出火山状的趋势。这些特性与反应对环氧丙烷的选择性密切相关。Ag的（为Mo-W）/的ZrO ₂（pH为10）的ZrO单斜晶相的最高分数₂和表面酸性对碱度的比值显示出对环氧丙烷的选择性最高（68％）。