CaO改性对CuZnAlZr催化剂在合成气制低碳醇中性能的影响

采用机械混合法和共沉淀法制备了CaO改性CuZnAlZr氧化物催化剂,在高压微型固定床反应器上考察了其在合成气制低碳醇反应中的催化性能,利用粉末X射线衍射(XRD)、低温氮气吸附-脱附、H2程序升温还原(H2-TPR)和二氧化碳吸附-脱附(CO2-TPD)等技术对催化剂进行了表征.结果显示:CaO改性对CuZnAlZr催化剂的织构性质没有明显的影响;但共沉淀法制备的CaO改性CuZnAlZr催化剂具有弱碱性和中等强度两种碱性中心,且有较多的碱中心数量;而未改性的CuZnAlZr催化剂只具有弱碱性中心.CO加氢反应结果表明:经共沉淀法制备的CaO改性CuZnAlZr催化剂对C2+醇的生成有明显的促进作用.

Effect of CaO Modification on Performance of CuZnAlZr Catalyst in Synthesis of Higher Alcohols from Synthesis Gas

CaO modified CuZnAlZr mixed oxide catalysts were prepared by mechanical mixing and co-precipitation methods,and their catalytic performances for CO hydrogenation to higher alcohols were investigated using a continuous flow high-pressure fixed-bed micro-reactor.The catalysts were characterized by X-ray diffraction(XRD),N2-adsorption-desorpotion,temperature-programmed reduction of H2(H2-TPR),and temperature-programmed desorption of CO2(CO2-TPD).The results showed that doping with CaO did not alter the textural properties of the catalyst,but increased the number of basic sites.Furthermore,the CaO-modified CuZnAlZr catalysts possessed both weak and medium strength basic sites,while unmodified CuZnAlZr catalyst possessed only weak basic sites.Catalytic performance,assessed by CO hydrogenation to C2+ alcohols,was improved in the CaO-doped CuZnAlZr catalyst relative to the undoped catalyst.