Ni-Ce/Al_2O_3催化剂上CH_4、CO_2和O_2催化重整制合成气

A Study of Ni-Ce/Al_2O_3 Catalysts for Catalytic Reforming of CH_4, CO_2 and O_2 to Syngas

采用TG、TPR、XRD、XPS等多种手段对Ni_Ce/Al2 O3 催化剂进行了研究 ,考察了催化剂的制备方法及预处理条件等对催化剂性能的影响 .结果表明 ,较佳的催化剂焙烧温度为 780℃ ,还原温度为 775℃ .在浸渍法制备的催化剂中 ,Ni物种主要以NiAl2 O4 尖晶石的形式存在 ;而共沉淀法制备的催化剂的表面则存在着较多的氧化镍 ,镍铝尖晶石的晶型结构较差 ,晶粒细小 ,在反应过程中可全部被还原成具有催化活性的金属镍物种 。

The Ni-Ce/Al 2O 3 catalysts were studied by TG, TPR, XRD, XPS. The effects of preparation methods of Ni-Ce/Al 2O 3 and pretreatment conditions on catalytic performance were investigated. The results revealed that the optimum calcination temperature was 780 ℃ and the proper reduction temperature was 775 ℃. Ni species in the form of NiA 2lO 4 were dispersed on the surface and the bulk phase of the catalyst prepared by impregnation. Meanwhile, there existed an amount of nickel oxide species on the surface of the catalyst prepared by co-precipitation. On the other hand, small-sized crystal of NiAl 2O 4 with defective crystalline structure was formed by co-precipitation, which can be reduced completely to Ni° species with catalytic activity. Thus, the Ni-Ce/Al 2O 3 catalyst prepared by co-precipitation exhibited better catalytic performance for such reactions.