等离子体辅助柠檬酸络合浸渍法制备Ni基催化剂及其CO_(2)甲烷化反应催化性能  

Ni-based catalysts prepared by plasma-assisted citric acid complexation impregnation and their catalytic performance for CO_(2) methanation

作　　者：彭雨欣 肖鑫[1] 梅加 储伟[1] PENG Yuxin;XIAO Xin;MEI Jia;CHU Wei(School of Chemical Engineering,Sichuan University,Chengdu 610065,Sichuan,China)

机构地区：[1]四川大学化学工程学院,四川成都610065

出　　处：《低碳化学与化工》2023年第3期89-97,共9页Low-Carbon Chemistry and Chemical Engineering

摘　　要：高活性、高稳定性的CO_(2)甲烷化催化剂对于合成天然气的生产以及CO_(2)减排至关重要。采用柠檬酸络合浸渍,等离子体处理再焙烧制备了一系列CeO_(2)修饰的Ni基催化剂用于CO_(2)甲烷化反应。在等离子体和柠檬酸的协同作用下,活性金属Ni高度分散。研究了柠檬酸和总金属阳离子(Ni2+、Ce3+及Mg2+之和)的物质的量之比(C/I值,0.5、1.0、1.5和2.0)对催化剂结构和低温CO_(2)甲烷化活性的影响。结合H_(2)-TPR、CO_(2)-TPD和XPS表征分析发现,改变C/I值可以有效调节金属-载体相互作用、表面碱度和氧空位相对含量,从而调控CO_(2)甲烷化活性。随着C/I值增加,NiCe-CP-x(x=0.5,1.0,1.5,2.0)的催化性能先增加后降低。最佳C/I值为1.5,此时NiCe-CP-1.5催化剂在低温240℃下,CO_(2)转化率达到81.5%,CH_(4)选择性为99.0%。在300℃下对催化剂进行了80 h的稳定性测试。结果显示,CO_(2)转化率保持在90%左右,没有明显的失活现象,催化剂性能稳定。Highly active and stable CO_(2) methanation catalysts are critical to the production of synthetic natural gas and CO_(2) emission reduction.A series of CeO_(2)-modifed Ni-based catalysts for CO_(2) methanation reaction were prepared by citric acid complexation impregnation,plasma treatment and calcination.The active metal Ni is highly dispersed by a synergetic effect of plasma and citric acid.The effect of the molar ratio of citric acid to total metal cations(sum of Ni2+,3+Ce and Mg2+)(C/I values,0.5,1.0,1.5 and 2.0)on the structure and low-temperature CO_(2) methanation activity of the catalyst were studied.Combined with H_(2)-TPR,CO_(2)-TPD,and XPS characterization analysis,it is found that changing the C/I values can effectively regulate the interaction between the metal and the support,surface alkalinity and the relative content of oxygen vacancies,thus controlling the CO_(2) methanation activity.The catalytic performance of NiCe-CP-x(x=0.5,1.0,1.5,2.0)first increases and then decreases with the increase of C/I values.The optimal C/I values is 1.5,where the CO_(2) conversion rate and CH_(4) selectivity of NiCe-CP-1.5 catalysts can achieve 81.5%and 99.0%at 240℃,respectively.The stability of the catalyst was tested for 80 h at 300℃.The results show that the CO_(2) conversion rate remains around 90%,there is no obvious deactivation and the catalytic performance of the catalyst is stable.

关 键 词：CO_(2)甲烷化 柠檬酸络合浸渍 NI基催化剂 等离子体 CeO_(2)助剂 

分 类 号：TQ203.2[化学工程—有机化工] O643.3[理学—物理化学]