CO2加氢经甲醇串联催化一器化制二甲醚用的高效混合型催化剂  

A Highly Efficient Hybrid Catalyst for ″One-pot″ Two-step Catalytic Synthesis of Dimethyl Ether from (CO_2+H_2) via CH_3OH

作　　者：范俊杰[1] 李海燕[1] 林国栋[1] 张鸿斌[1] 

机构地区：[1]厦门大学化学化工学院,固体表面物理化学国家重点实验室,醇醚酯化工清洁生产国家工程实验室,福建厦门361005

出　　处：《厦门大学学报（自然科学版）》2010年第6期749-755,共7页Journal of Xiamen University：Natural Science

基　　金：“973”计划(2009CB939804);福建省重大专项专题项目(2009HZ0002-1);福建省发改委高技术项目(闽发改高技2009-1030)

摘　　要：将CO2加氢用的金属Co修饰碳纳米管(x%Co/CNT)促进的Cu-Zn-Zr基催化剂与甲醇脱水用的HZSM-5沸石分子筛按一定比例和一定方式混合,制成CO2加氢经甲醇串联催化一器化制二甲醚(DME)用的双功能混合型催化剂,记为(CuiZnjZrk-y%(x%Co/CNT))-z%HZSM-5.实验结果显示,在经优化的(Cu8Zn2Zr5-10%(4.5%Co/CNT))-40%HZSM-5催化剂上,在5.0 MPa,523 K,V(H2)∶V(CO2)∶V(N2)=69∶23∶8,GHSV=20 000 mL/(h.g)的反应条件下,CO2加氢的转化频率达到5.62×10-3s-1,分别是相同条件下非促进的单功能原基质Cu8Zn2Zr5催化剂和非促进的双功能混合型催化剂Cu8Zn2Zr5-40%HZSM-5上相应值(4.26×10-3和4.96×10-3s-1)的1.32和1.13倍;在CO2加氢转化产物中,DME的选择性达到约80%,相应的DME时空产率为343 mg/(h.g).催化剂的表征研究显示,适量HZSM-5沸石分子筛与Cu-Zn-Zr基催化剂混合能将初级反应产生的甲醇大部分转化为DME;Co修饰CNT促进的催化剂对H2优良的吸附活化性能对CO2加氢转化频率的显著提高起着重要作用.With the homemade Co-decorated multiwalled carbon nanotubes（x%Co/CNT） as promoter,a type of hybrid catalysts of the Co-decorated CNT-promoted CuZnZr-oxide hybridized with HZSM-5 zeolite molecular sieve,（CuiZnjZrk-y%（x%Co/CNT））-z%HZSM-5,were developed.The catalyst displays excellent performance for dimethyl ether（DME） synthesis from（CO2＋H2） via methanol in heterogeneous ″one-pot″ reactions.Over a（Cu8Zn2Zr5-10%（4.5%Co/CNTs））-40%HZSM-5 catalyst under reaction conditions of 5.0 MPa,523 K,V（H2）∶V（CO2）∶V（N2）=69∶23∶8,GHSV=20 000 mL/（h·g）,the observed turnover frequency（TOF） of CO2 hydrogenation reached 5.62×10–3 s–1.This value was 1.32 and 1.13 times that（4.26×10–3 s–1 and 4.96×10–3 s–1） of the CNT-free mono-functional catalyst Cu8Zn2Zr5 and the CNT-free bi-functional hybrid catalyst Cu8Zn2Zr5-40%HZSM-5,respectively.C-based selectivity of DME in the CO2 hydrogenation products reached about 80%,with corresponding space time yield（STY） reached 343 mg/（h·g）.Characterization of the catalyst revealed that the excellent capability of the Co-decorated CNT-promoted bi-functional hybrid catalyst for adsorbing H2 played an important role in facilitating the increase of TOF of CO2 hydrogenation.

关 键 词：Co-修饰多壁碳纳米管 CNT促进CuiZnjZrk-氧化物-HZSM-5混合型催化剂 CO2加氢 二甲醚合成 

分 类 号：O643.36[理学—物理化学]