尿素水解均匀沉淀法制Cu/ZnO/Al2O3甲醇合成催化剂

甲醇是富氯液体，可通过水蒸气重整制氢用于燃料电池的氢源，是最有希望成为燃料电池电动汽车的燃料，目前这方面的研究颇受重视。现代甲醇工业是通过合成气在催化剂作用下反应制得的，所用催化剂主要为Cu／ZnO／Al2O3。为了进一步提高催化剂的性能，近年来关于催化剂制备方法的文献发表较多。吴晓晖等考察了草酸盐胶体法制备Cu／ZnO／Al2O3甲醇合成催化剂的性能，洪中山等用凝胶网格共沉淀法制得Cu／ZnO／Al2O3甲醇合成催化剂，郭宪吉等则考察了添加Mn助剂对Cu／ZnO／Al2O3甲醇合成催化剂的影响。

PREPARATION OF Cu/ZnO/Al2O3 CATALYSTS FOR METHANOL SYNTHESIS BY UREA-HYDROLYZED PRECIPITATION METHOD

In view of not uniformity in conventional coprecipitation preparation, urea was used as the precursor of precipitator to prepare Cu/ZnO/Al2O3 catalysts for methanol synthesis. In the method, urea was dissolved in nitrate solution and hydrolyzed to produce OH－ as precipitator after the solution was heated to 90 ℃. After 6 h, the precipitation was accomplished. The evaluation results of the catalyst activity showed that this catalyst had comparable catalytic activities to the industrial catalyst, and reached its maximum activity at 250 ℃. At reaction conditions of 250 ℃, 3 MPa, and SV=7 600 h－1, the STY of methanol was 0.38 g/(mL·h) with syngas compositing of H2,CO, CO2, and N2 at molar ratio of 65.9∶27.1∶2.9∶4.1. X-ray Diffraction (XRD) revealed that the particle size of CuO and ZnO was about 200 nm, and Al existed in the form of ZnAl2O4 spinel in the catalysts.