热处理条件对完全液相法制Cu-Zn-Al催化剂结构及CO加氢性能的影响

Effects of Heat Treatment Methods on the Structure of Cu-Zn-Al Catalyst Prepared by Liquid Phase Method and the Catalytic Performance of CO Hydrogenation

采用完全液相法制备Cu-Zn-Al浆状催化剂,利用XRD、 H_2程序升温还原、 N_2吸附-脱附、 XPS对催化剂进行表征,并在浆态床反应器中评价其CO加氢性能,考察了前驱体的热处理条件(常压、中压和密闭高压)对催化剂结构和性能的影响.结果表明,常压热处理所制催化剂,比表面积较大,活性物种的分散度和表面铜锌比均较高,有利于反应气体的吸附和扩散, CO加氢活性较高;采用加压热处理时, Cu晶粒较大,且有尖晶石相的生成,增强了Cu、 Zn、 Al物种之间的相互作用,影响了Cu物种的还原能力和催化剂的表面酸性,使催化剂具有一定的生成低碳醇能力.

The Cu-Zn-Al slurry catalyst was prepared by the complete liquid phase method,and it was characterized by XRD,H2 temperature-programmed reduction,N2 adsorption-desorption and XPS.The CO hydrogenation performance was evaluated in a slurry bed reactor.The effects of the heat treatment conditions(normal pressure,medium pressure and closed high pressure)of the precursor on the structure and properties of the catalyst were investigated.The results show that the catalyst prepared by atmospheric pressure heat treatment has larger specific surface area,higher dispersion of active species and higher ratio of copper to zinc on the surface,which is beneficial to the adsorption and diffusion of reaction gases,CO hydrogenation activity is higher;When using pressurized heat treatment,Cu crystal grains are larger and spinel phase is formed,which enhances the interaction between Cu,Zn and Al species,affects the reduction ability of Cu species and the surface acidity of the catalyst,and makes the catalyst has a certain ability to produce ethanol.