NiO/γ-Al2O3催化剂中NiO与γ-Al2O3间的相互作用

利用溶胶－凝胶法制备了不同含量的 ＮｉＯ／γ－Ａｌ_２Ｏ_３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－Ａｌ_２Ｏ_３间具有强相互作用．详细地讨论了Ｎｉ物种的还原状态与以“Ｎｉ~０”为活性中心的催化反应的活性之间的关系．溶胶－凝胶法制备的催化剂经高温焙烧后，Ｎｉ以一种类尖晶石结构的固溶体形式存在，这种固溶体态尖晶石可能会抑制Ｎｉ的烧结和流失，提高催化剂的稳定性．

Interaction of NiO with γ-Al2O3 Supporter of NiO/γ-Al2O3 Catalysts

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 performance 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.