Coking-resistant Ni-ZrO_2/Al_2O_3 catalyst for CO methanation

作     者：Qing Liu Fangna Gu Jiajian Gao Huifang Li Guangwen Xu Fabing Su 

作者机构：State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences 

出 版 物：《Journal of Energy Chemistry》 (能源化学（英文版）)

年 卷 期：2014年第23卷第6期

页      面：761-770页

核心收录：

学科分类：081705[工学-工业催化] 08[工学] 0817[工学-化学工程与技术] 

基　　金：supported by the National Natural Science Foundation of China(No.21476238) the National Basic Research Program(No.2014CB744306) the National Key Technology R&D Program of China(No.2010BAC66B01) the"Strategic Priority Research Program"of Chinese Academy of Sciences(Nos.XDA07010100 and XDA07010200) 

主　　题：Ni/γ-A1203 ZrO2 coke resistance syngas methanation 

摘      要：Highly coke-resisting ZrO2-decorated Ni/A1203 catalysts for CO methanation were prepared by a two-step process. The support was first loaded with NiO by impregnating method and then modified with ZrO2 by deposition-precipitation method （IM-DP）. Nitrogen adsorption- desorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetdc analysis, H2 temperature- programmed reduction and desorption, NH3 temperature-programmed desorption, and zeta potential analysis were employed to characterize the samples. The results revealed that, compared with the catalysts with the same composition prepared by co-impregnation （CI） and sequential impregnation （SI） methods, the Ni/A1203 catalyst prepared by IM-DP showed much enhanced catalytic performance for syngas methanation under the condition of atmospheric pressure and a high weight hourly space velocity of 120000 mL.g-1 .h-1. In a 80 h life time test under the condition of 300-600 ~C and 3.0 MPa, this catalyst showed high stability and resistance to coking, and the amount of deposited carbon was only 0.4 wt%. On the contrary, the deposited carbon over the catalyst without ZrO2 reached 1.5 wt% after a 60 h life time test. The improved catalytic performance was attributed to the selective deposition of ZrO2 nanoparticles on the surface of NiO rather than A1203, which could he well controlled via changing the electrostatic interaction in the DP procedure. This unique structure could enhance the dissociation of CO2 and generate surface oxygen intermediates, thus preventing carbon deposition on the Ni particles in syngas methanation.