过渡金属改性的Cr-Ce-O催化剂氧化氯苯性能

以氯苯为含氯挥发性有机污染物探针物，以稀土基CeO₂为基底活性氧化物，采用柠檬酸络合法制备Cr-Ce-O催化剂，考察Cr/Ce物质的量比、过渡金属氧化物掺杂及掺杂量、载体和焙烧温度对Cr-Ce-O催化剂催化氧化氯苯性能的影响；采用XRD、BET、SEM、H₂-TPR、XPS等表征技术分析催化剂的基本特性.研究表明，Cr₂O₃和CeO₂间形成了CrCeO_x固溶体，掺杂有ZrO₂的Cr₂O₃-CeO₂/Al₂O₃催化剂其比表面积得到显著提升，且载体对催化剂活性组分形态结构产生重要影响，其中以焙烧温度为400℃，堇青石为载体的催化剂氧化活性较优.研究发现，ZrO₂掺杂量亦对催化剂氧化活性产生显著性影响，当Zr/Cr物质的量比为1：2时，Cr₂O₃-CeO₂-ZrO₂/堇青石催化剂表现最佳，催化氧化氯苯转化率可达92.7%（反应温度为350℃），这主要是由于ZrO₂掺入促进了CeO₂和Ce₂O₃，Cr₂O₃和ZrO₂间的相互作用，氧空位增加促使表面活性氧（O_sur）增多.

Catalytic oxidation of chlorobenzene over Cr-Ce-O catalysts modified by transition metals

Chlorobenzene was applied as a probe for chlorinated volatile organic compounds, and rare-earth based CeO₂ was used as the active oxide. The Cr-Ce-O catalysts were prepared by complexation method with citric acid adding. The effects of the molar ratio of Cr/Ce, the doping and amount of transition metal oxide, the supports, and calcination temperature on chlorobenzene oxidation were investigated. The as-prepared catalysts were characterized by XRD, BET, SEM, H₂-TPR and XPS. CrCeO_xsolid solution was formed between Cr₂O₃ and CeO₂, and the specific surface area of Cr₂O₃-CeO₂/Al₂O₃ catalyst with ZrO₂ doping was improved, significantly. The supports exhibited an important influence on the morphology and structure of the active components. The oxidation activity of these catalysts with calcination temperature at 400℃ and cordierite support was higher. The results also exhibited that the ZrO₂ doping also displayed a significant effect on the oxidation activity. When the molar ratio of Zr/Cr was 1:2, the Cr₂O₃-CeO₂-ZrO₂/cordierite catalyst showed the highest performance, and the conversion rate of chlorobenzene oxidation was 92.7% (the reaction temperature was 350℃). It was mainly attributed to ZrO₂ doping promoted the interaction between CeO₂ and Ce₂O₃, Cr₂O₃ and ZrO₂, and enhanced oxygen vacancy attributed to the increase of surface-active oxygen (O_sur).