NiO/γ-Al_2O_3催化剂中NiO与γ-Al_2O_3间的相互作用

Interaction of NiO with γ-Al_2O_3 Supporter of NiO/γ-Al_2O_3 Catalysts

利用溶胶－凝胶法制备了不同含量的ＮｉＯ／γ－Ａｌ２Ｏ３催化剂，通过ＸＲＤ，ＸＰＳ和ＴＰＲ等技术考察了制备方法，ＮｉＯ含量和焙烧温度对催化剂结构和Ｎｉ存在状态的影响，发现溶胶－凝胶法制备的催化剂活性组分ＮｉＯ与担体γ－Ａｌ２Ｏ３间具有强相互作用。

A series of NiO/γ-Al_2O_3 catalysts were prepared by sol-gel method. The effects of the methods of preparation, the nickel content and the calcined temperature on the structure and existing forms of nickel species of NiO/γ-Al_2O_3 catalysts were investigated using XRD, XPS and TPR. The results suggested that the interaction between NiO and γ-Al_2O_3 affected the oxidic nickel speies. Nickel oxide was found to appear in the catalysts in three forms, as 'free', 'dispersed' and 'fixed' oxides. The occurrence of the fixed form of the oxide in the catalysts was connected with the formation of nickel aluminate. The effect of the reaction of these different nickel species on the per- formance of the catalysts was dicussed. For the catalysts prepared by sol-gel method, after calcined at higher temperature, nickel species present as a spinel-like structure solid solution, which could re- strain nickel loss and sintering and improve the thermal stability of catalysts.