Sn助剂调控Co/ZrO_(2)催化剂用于CO_(2)选择性加氢制CO  

Selective hydrogenation of CO_(2)to CO over Co/ZrO_(2)catalysts regulated by Sn promoter

作　　者：袁金标 陈杰 胥月兵 刘冰 刘小浩 YUAN Jinbiao;CHEN Jie;XU Yuebing;LIU Bing;LIU Xiaohao(School of Chemical and Material Engineering,Jiangnan University,Wuxi 214122,Jiangsu,China)

机构地区：[1]江南大学化学与材料工程学院,江苏无锡214122

出　　处：《低碳化学与化工》2024年第11期21-27,共7页Low-Carbon Chemistry and Chemical Engineering

基　　金：国家重点研发计划(2023YFB4103201);国家自然科学基金(22379053,22372073)。

摘　　要：将CO_(2)通过逆水煤气变换(RWGS)反应转化为CO能够有效缓解因CO_(2)排放引发的环境问题,然而CO_(2)的有效活化以及抑制副产物CH4的生成是RWGS反应的关键难点。将不同掺杂量(质量分数,下同)的Sn引入5Co/ZrO_(2)(Co质量分数为5%)中进行修饰,制备了5Cox Sn/ZrO_(2)(x=1、3或5,分别对应Sn掺杂量为1%、3%或5%)催化剂,并对5Co/ZrO_(2)和5Cox Sn/ZrO_(2)的催化CO_(2)加氢反应性能评价过程中的各项实验参数进行了调节和筛选,用于探究Sn助剂对活性组分以及催化性能的影响。其中,5Co5Sn/ZrO_(2)具有最佳的RWGS催化性能,其在600°C下预还原2 h后,在反应温度为500℃、压力为0.1 MPa和体积空速为36000 mL/(g·h)的反应条件下,CO_(2)转化率达到11.9%,CO选择性为99.4%。采用XRD、H_(2)-TPR和H_(2)-TPD等表征方法综合分析了Sn助剂在CO_(2)加氢反应过程中的作用。结果表明,Sn助剂的引入将CO_(2)加氢反应从甲烷化调控为RWGS反应。经过还原预处理后,Sn与Co物种形成了Co-Sn合金,新的活性位点减弱了催化剂表面吸附CO_(2)、H_(2)和CO的性能。与5Co/ZrO_(2)相比,5Co5Sn/ZrO_(2)的H_(2)吸附和活化性能减弱,CO_(2)和CO吸附量大幅降低,降低了CO_(2)加氢的活性并抑制了CO_(2)深度加氢,使得催化剂的催化性能降低,CH4选择性降低,CO选择性升高至约100%。The conversion of CO_(2)to CO via reverse water gas transformation(RWGS)reaction can present a promising strategy to mitigate the environmental impact of CO_(2)emission.However,the RWGS reaction encounters notable challenges,such as the efficient activation of CO_(2)and the suppressed generation of CH4.Different doping contents(mass fractions,the same below)of Sn were introduced into 5Co/ZrO_(2)(Co mass fraction of 5%)for modification,and 5CoxSn/ZrO_(2)(x=1,3 or 5,corresponding to Sn doping content of 1%,3%or 5%)catalysts were prepared.The experimental parameters for evaluating the catalytic performances of 5Co/ZrO_(2)and 5CoxSn/ZrO_(2)in CO_(2)hydrogenation reaction were adjusted and screened to explore the influence of Sn additives on the active components and catalytic performance.Among them,5Co5Sn/ZrO_(2)shows the best RWGS catalytic performance.After pre-reduction for 2 h at 600℃,under reaction conditions of temperature of 500℃,pressure of 0.1 MPa and space velocity of 36000 mL/(g·h),the CO_(2)conversion rate reaches 11.9%,and the CO selectivity is 99.4%.The role of Sn promoter in CO_(2)hydrogenation reaction was comprehensively analyzed by characterization methods such as XRD,H_(2)-TPR,and H_(2)-TPD.The results indicate that the introduction of Sn regulates the CO_(2)hydrogenation reaction from methanation to RWGS.After reduction,Sn and Co species form Co-Sn alloy,and new active sites reduce the ability of the catalyst surface to adsorb CO_(2),H_(2) and CO.Compared with 5Co/ZrO_(2),5Co5Sn/ZrO_(2)shows weaker adsorption and activation ability of H_(2) and much lower adsorption amount of CO_(2)and CO,which reduces the activity of CO_(2)hydrogenation and inhibits the deep CO_(2)hydrogenation,resulting in a decrease in the catalytic performance of the catalyst,a decrease in CH4 selectivity and an increase in CO selectivity to about 100%.

关 键 词：CO_(2)加氢 RWGS 选择性转换 Co-Sn合金 化学吸附 

分 类 号：TQ426[化学工程]