Fe掺杂对Ni-Fe/Al_(2)O_(3)催化CO_(2)甲烷化性能的影响  

Effect of Fe-doping on catalytic performance of Ni-Fe/Al_(2)O_(3)for CO_(2)methanation

作　　者：覃毅 潘柳依[1] 卢晨阳 王颖侠 牛梦龙 李冬[1] QIN Yi;PAN Liuyi;LU Chenyang;WANG Yingxia;NIU Menglong;LI Dong(School of Chemical Engineering,Northwest University,Xi'an 710127,Shaanxi,China;School of Chemistry and Chemical Engineering,Chongqing University,Chongqing 400044,China;School of Chemistry and Chemical Engineering,Xi'an Shiyou University,Xi'an 710065,Shaanxi,China)

机构地区：[1]西北大学化工学院,陕西西安710127 [2]重庆大学化学化工学院,重庆400044 [3]西安石油大学化学化工学院,陕西西安710065

出　　处：《精细化工》2025年第1期119-127,共9页Fine Chemicals

基　　金：国家自然科学基金项目(22308277);陕西省自然科学基础研究计划项目(2021JLM-19);陕西省教育厅专项计划项目(20JK0842);陕西省重点研发计划项目(2022GY-154);重庆市博士后科学基金项目(CSTB2022NSCQ-BHX0021)。

摘　　要：以纳米Al_(2)O_(3)为载体、Ni(NO_(3))_(2)•6H_(2)O为镍盐前体、Fe(NO_(3))_(3)•9H_(2)O为铁盐前体,通过水热法制备了前驱体,再经H_(2)还原制备了Fe掺杂的Ni基催化剂(Ni-Fe/Al_(2)O_(3))。采用SEM、EDS、XRD、XPS对其进行了表征,利用固定床评价了Ni-Fe/Al_(2)O_(3)催化CO_(2)甲烷化的性能,探究了Fe与Ni的协同作用及Fe掺杂对CO_(2)甲烷化反应的影响。结果表明,与未掺杂Fe的Ni/Al_(2)O_(3)相比,以n(Ni)∶n(Fe)=9∶1制备的Ni-Fe/Al_(2)O_(3)(金属负载量约为Al_(2)O_(3)物质的量的20%)具有更优异的CO_(2)甲烷化催化性能,在375℃下,CO_(2)转化率达到84.2%,CH4选择性达到83.5%。密度泛函理论计算表明,Fe的引入稀释了Ni-Fe表面并改变了Ni的电子性质,Ni-Fe/Al_(2)O_(3)表面不仅增强了对CO_(2)的吸附,提高了CO_(2)的活化程度,而且使H_(2)的解离更容易,有利于加氢反应的进行;此外,Fe的引入改变了CO_(2)的反应途径,使反应向CH4生成方向进行,具体路径为:CO_(2)*→HCOO*→HCOOH*→H_(2)COOH*→H_(2)CO*→H_(3)CO*→CH_(4)*。Fe doped Ni based catalyst(Ni-Fe/Al_(2)O_(3))was prepared from H_(2)reduction of its precursor,which was synthesized via hydrothermal method using nano Al_(2)O_(3)as carrier,Ni(NO_(3))_(2)•6H_(2)O as nickel salt precursor,and Fe(NO_(3))_(3)•9H_(2)O as iron salt precursor,and characterized by SEM,EDS,XRD and XPS.The catalytic performance of Ni-Fe/Al_(2)O_(3)on CO_(2)methanation was evaluated in a fixed bed,with the synergistic effect of Fe and Ni and the effect of Fe doping on CO_(2)methanation were further explored.The results showed that compared with Ni/Al_(2)O_(3)without Fe doping,Ni-Fe/Al_(2)O_(3)(the metal load is 20%of the Al_(2)O_(3)substance amount)exhibited better catalytic performance for CO_(2)methanation.Under the conditions of Ni-Fe/Al_(2)O_(3)prepared with n(Ni)∶n(Fe)=9∶1 as catalyst and 375℃,the CO_(2)conversion rate reached 84.2%,and the CH4 selectivity reached 83.5%.Density functional theory calculations indicated that the introduction of Fe diluted the surface of Ni-Fe and changed its electronic properties.The Ni-Fe surface not only enhanced the CO_(2)adsorption on the catalyst surface and improved the CO_(2)activation degree,but also made the H_(2)dissociation easier,which was conducive to the progress of hydrogenation reactions.In addition,the introduction of Fe changed the reaction pathway of CO_(2),making the reaction proceed in the direction of CH4 formation.The specific pathway was CO_(2)*→HCOO*→HCOOH*→H_(2)COOH*→H_(2)CO*→H_(3)CO*→CH_(4)*.

关 键 词：CO_(2)加氢 甲烷化 双金属催化剂 协同作用 密度泛函理论 催化技术 

分 类 号：O643.36[理学—物理化学] TQ203.2[理学—化学]