CO2加氢制甲醇用碳纳米管促进的高效新型CuO-ZnO-ZrO_2基催化剂

A Novel Co-decorated CNT-promoted CuO-ZnO-ZrO_2 Catalyst for CO_2 Hydrogenation to Methanol

用一种金属Co修饰多壁碳纳米管基复合材料(y%Co/CNT)作为促进剂,制备一种高效新型的y%Co/CNT促进CuO-ZnO-ZrO2基催化剂(记为CuiZnjZrk-x%(y%Co/CNT)),考察其对CO2加氢制甲醇的催化性能.实验结果显示,在组成经优化的Cu8Zn2Zr5-10%(4.5%Co/CNT)催化剂上,5.0 MPa,523 K,V(H2)∶V(CO2)∶V(N2)=69∶23∶8,GHSV=25 000 mL/(h.g)的反应条件下,CO2加氢的转化频率达4.99×10-3s-1,分别是相同条件下非促进的原基质Cu8Zn2Zr5和单纯CNT促进的对应物Cu8Zn2Zr5-10%CNT上的相应值(4.31×10-3和4.64×10-3s-1)的1.16和1.08倍;催化剂的表征结果显示,金属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(TOF)的显著提高起主要作用.在CO2加氢产物中甲醇的C-基选择性达97.9%,单程时空产率为699 mg/(h.g),具有实用前景.

A type of Co-decorated CNT-promoted CuO-ZnO-ZrO2 catalysts was developed.The catalyst displays excellent performance for CO2 hydrogenation to methanol.Over a Cu8Zn2Zr5-10%（4.5%Co/CNT） catalyst under reaction conditions of 5.0 MPa,523 K,V（H2）∶V（CO2）∶V（N2） = 69∶23∶8 and GHSV = 25 000 mL/（h·g）,the observed turnover frequency（TOF） of CO2 hydrogenation,i.e.,the number of CO2-molecule hydrogenated on unit site of exposed Cu0 per second（s-1）,reached 4.99×10-3 s-1.This value was 1.16 and 1.08 times that（4.31×10-3 and 4.64×10-3 s-1） of the CNT-free substrate Cu8Zn2Zr5 and the simple CNT-promoted counterpart Cu8Zn2Zr5-10%CNT,respectively,under the same reaction conditions.The selectivity of CH3OH in the CO2 hydrogenation products reached 97.9%,with corresponding STY reaching 699 mg/（h·g）.Characterization of the catalyst revealed that the excellent capability of the Co-decorated CNT-promoted catalyst for adsorbing and activating H2 played an important role in facilitating the increase of rate of surface CO2 hydrogenation reactions.