铜锌盐的溶剂对完全液相法制备的CuZnAl催化剂催化性能的影响

CuZnAl催化剂在合成气催化转化中被广泛应用。以异丙醇铝为铝源，分别以水、乙醇或乙二醇作为硝酸铜和硝酸锌的溶剂，采用完全液相法制备CuZnAl催化剂，考察了铜锌盐的溶剂对催化剂用于浆态床CO加氢性能的影响，并用XRD、H2 TPR、XPS、NH3 TPD和N2物理吸附等手段对催化剂进行表征。结果表明，溶解铜锌盐的溶剂不同，会造成催化剂中Cu和ZnO的分散度、Cu物种的还原性能、表面元素组成以及表面酸量存在差异，从而影响其催化性能。以乙二醇为溶剂制备的CuZnAl催化剂中，Cu的晶粒较大而ZnO的分散度最好，表面Cu含量最高，Cu组分与Zn和Al组分间有较强的相互作用，且有较多的表面弱酸量及较大的孔容，其催化CO加氢产物中二甲醚和烃的选择性较高，且有一定量C2+OH的生成，C2+OH在总醇中占比达2711%，但CO转化率较低。以水和乙醇为溶剂制备的CuZnAl催化剂，CO转化率较高，但醇产物以甲醇为主。

Effects of Solvent for Copper and Zinc Nitrateon the Catalytic Performance of CuZnAl Catalyst Prepared by Complete Liquid-Phase Method

CuZnAl catalysts are widely used in the conversion of syngas. In this paper, CuZnAl catalysts were prepared by using complete liquid phase method with aluminum isopropoxide as aluminum source, deionized water, ethanol/ethylene glycol as a solvent for copper nitrate and zinc nitrate. They were characterized by XRD，H2 TPR，XPS，NH3 TPD and N2 physical adsorption desorption. The impacts of solvent for copper and zinc nitrate on the CO hydrogenation performance were tested in slurry bed reactor. Results indicate that different solvents lead to the differences of the dispersion of Cu and ZnO, the reduction performance of Cu species, surface element composition and surface acid in the catalysts, thus affecting their catalytic performance. The CuZnAl catalyst prepared with ethylene glycol as solvent presents the largest particle size of Cu, the highest dispersion of ZnO, the highest surface content of Cu, the strongest interaction between Cu component and Zn and Al component. It has suitable amount of surface weak acid and appropriate large pore volume, which leads to high selectivity of DME and hydrocarbon, with a certain amount of C2+OH accounting for up to 2711% in ROH with low CO conversion. The CuZnAl catalyst prepared with water and ethanol as solvent shows high CO conversion whereas methanol dominates as major product.