La_2O_3对Ni-Mo/γ-Al_2O_3催化剂CO和CO_2甲烷化的影响

Effect of La2O3 on Methanation of CO and CO2 overNiMo/Al2O3 Catalyst

采用浸渍法制备了一系列ＮｉＭｏＬａ／γＡｌ２Ｏ３催化剂并测定了催化剂的ＣＯ和ＣＯ２甲烷化活性。采用ＴＥＭ，ＸＰＳ和ＣＯ化学吸附等手段研究了催化剂的表面性质。结果表明，Ｌａ２Ｏ３的加入提高了ＮｉＭｏ／γＡｌ２Ｏ３催化剂的ＣＯ和ＣＯ２甲烷化活性，增加了催化剂中Ｎｉ的分散度、活性表面积及催化剂表面Ｎｉ原子的浓度。

A series of NiMo/Al2O3 methanation catalysts containing La2O3 were prepared by impregnation. The activities of catalysts for CO and CO2 methanation were investigated. The surface behaviour of the catalysts and the role of lanthanum in NiMoLa/Al2O3 were studied by TEM, XPS and chemisorption of CO, respectively. The experimental results show that the addition of La2O3 greatly increases the activity, the selectivity of catalyst and the heat value of the product. The La2O3 increases the concentration of nickel atoms on the surface of NiMo/Al2O3 catalyst and the active nickel surface area. At the same time, it also makes the crystalline granule of nickel smaller and affects the electronic structure of nickel. All these actions improve the catalytic activity.