摘要
采用共沉淀法合成了掺杂不同助剂的Cu-M/ZnO(Cu:ZnO物质的量比=5∶4,M=Zr^(4+)、Al3+、Mg2+,助剂含量为4.0%)用于催化草酸二甲酯(Dimethyl oxalate,DMO)选择加氢反应催化剂。结果表明,微量掺杂Al3+、Mg2+助剂嵌入于ZnO晶相,Zr^(4+)助剂嵌入Cu晶相均能显著促进Cu/ZnO催化剂中铜分散;其中,Mg^(2+)助剂能够有效增强Cu、ZnO物相间相互作用,Zr^(4+)助剂能够有效增强Cu、ZrO_(2)物相间相互作用。催化DMO加氢选择加氢反应,Cu/ZnO催化剂乙二醇(Ethylene glycol,EG)收率仅为75.0%,Cu-Al/ZnO、Cu-Zr/ZnO和Cu-Mg/ZnO催化剂的EG收率分别为90.0%、85.0%、95.0%。相比Cu/ZnO和Cu-Al/ZnO催化剂催化DMO选择加氢反应易于失活,Cu-Zr/ZnO和Cu-Mg/ZnO催化剂显现出优异稳定性,稳定反应时长超过100 h。催化剂构-效关系表明,Cu/ZnO和Cu-Mg/ZnO催化剂表面较高Cu+活性位以及充足Cu0活性位协同效应是其显现优异催化活性的主要因素。此外,Cu-Zr/ZnO和Cu-Mg/ZnO中较强的金属/氧化物相互作用能够有效抑制催化剂中铜纳米粒子于强放热反应中发生迁移、烧结,赋予催化剂优异的稳定性。
The Cu-M/ZnO catalysts(M=Zr4+,Al^(3+)and Mg^(2+))for dimethyl oxalate(DMO)selective hydrogenation to ethylene glycol(EG)were synthesized by the co-precipitation method.The properties of the as-synthesized catalysts were characterized by N2-physisorption,N2O-titration,XRD,H2-TPR,CO_(2)-TPD,SEM,FT-IR and XPS.It was found that the Cu dispersion could be effectively promoted by the dopants incorporated in the Cu/ZnO catalyst.Particularly,a trace amount of Mg^(2+)and Al^(3+)dopants could significantly reinforce the chemical interaction between the Cu and ZnO phases by embedding into the ZnO lattice,while the Cu/ZrO_(2)interaction could be improved with the introduction of Zr4+.For DMO gas-phase hydrogenation,the EG yield of the Cu/ZnO catalyst increased from 75.0%to 85.0%and 90.0%in the presence of Zr^(4+)and Al^(3+)dopants,respectively.Particularly,the EG selectivity of Cu-Mg/ZnO catalyst reached up to 95.0%with DMO completely converted for more than 100 h.The correlation between the catalytic behavior and physicochemical features of the Cu/ZnO based catalysts suggested that the surface Cu+sites was vital for the catalytic behavior with adequate Cu0 sites.Additionally,the strengthened Cu/oxide interaction favored the outstanding stability of the Cu-Zr/ZnO and Cu-Mg/ZnO catalyst for DMO hydrogenation.
作者
孔祥鹏
游新明
元培红
吴跃焕
王瑞虹
陈建刚
KONG Xiang-peng;YOU Xin-ming;YUAN Pei-hong;WU Yue-huan;WANG Rui-hong;CHEN Jian-gang(Department of Chemistry and Chemical Engineering,Taiyuan Institute of Technology,Taiyuan 030008,China;School of Chemistry and Chemical Engineering and Technology,North University of China,Taiyuan 030051,China;Center for Disease Control and Prevention,China Railway No.3 Engineering Group Co.,Ltd,Taiyuan 030012,China;State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China)
出处
《燃料化学学报（中英文）》
EI
CAS
CSCD
北大核心
2023年第6期794-803,共10页
Journal of Fuel Chemistry and Technology
基金
山西省高等学校科技创新项目(Grant STIP 2019L0928,2020L0658)
山西省1331工程资助。
