萤石结构铜-铈-氧催化剂组成与催化活性

Composition of fluorite type Cu-Ce-O catalysts and their oxidation activity

按不同的 Cu、Ce配比制备了 5种 Cu-Ce-O催化剂 ;与纯 Cu O和 Ce O2 相比 ,其 CO催化氧化活性均较高 .XRD测试显示 ,活性最高的 ( Cu O) 0 .1 5 -( Ce O2 ) 0 .85 催化剂上看不见 Cu O的特征峰 ,只显示 Ce O2 的萤石结构特性 ,说明高活性是由于 Cu O高度分散在 Ce O2 上所产生的协同效应所致 .对反应的动力学处理结果表明 ,其组成与活性的变化符合 Constable标绘的规律 ,表明它们是同一系列性质相似的催化剂 .还对这些催化剂进行了 H2 -TPR、O2 -TPD和 CO-TPD的表征以考察它们的氧和一氧化碳吸附量。

Five kinds of Cu-Ce-O catalysts with different n(Cu)/n(Ce) were prepared. Catalytic activities for CO oxidation are measured over these catalysts as well as over pure CuO and CeO2 catalysts. The results show that their catalytic activities were higher than those of pure CuO and CeO2. XRD spectra show that no characteristic peak of CuO can be found on the spectrum of the highest activity (CuO)0.15-(CeO2)0.85 catalyst, and only the characteristic peaks of fluorite type structure of CeO2 can be found. This means higher activity of the catalyst is caused by the synergism effect of highly dispersed CuO over CeO2. Kinetic parameters study of this system shows that it fits the rule of Constable plot very well, which means all of these five catalysts have similar properties. In order to study the effects of adsorption amounts of oxygen and carbon monoxide, and the reducibility of oxygen-contained species on catalytic activities of these catalysts, H2-TPR, O2-TPD and CO-TPD studies are carried out too.