收稿日期: 2016-01-11
网络出版日期: 2016-04-30
基金资助
国家自然科学基金资助项目(11375111, 21503260); 中国科学院战略性先导科技专项基金资助项目(XDA02040602); 上海市自然科学基金资助项目(14DZ1207600, 15ZR1444500)
Preparation of layered Cu/ZnO/Al2O3 catalyst and its catalytic performance for CO2 hydrogenation to methanol
Received date: 2016-01-11
Online published: 2016-04-30
以尿素为沉淀剂, 采用均相沉淀法成功制备了层状Cu/Zn/Al 水滑石化合物. 将前驱体材料经焙烧、还原后得到Cu/ZnO/Al2O3 催化剂, 并将其用于CO2 加氢合成甲醇反应. 采用X 射线衍射(X-ray diffraction, XRD)、热重(thermogravimetric, TG)分析、扫描电镜(scanning electron microscope, SEM)、X射线荧光(X-ray fluorescence, XRF)分析、N2吸附、H2 程序升温还原(H2-temperature program reduction, H2-TPR)、氧化亚氮(N2O)反应吸附、CO2程序升温脱附(CO2 temperature program desorption, CO2-TPD)技术对所制备的样品进行表征. 结果表明, 相对于传统共沉淀法, 以尿素作为沉淀剂, 通过均相沉淀法所制备的前驱体的结晶度更高、催化剂比表面积更大、金属Cu 的分散度更好. 另外, 采用回流处理可以获得更好的效果. 活性评估结果表明, O2转化率随金属Cu 比表面积的增大而增加, 而甲醇选择性则与催化剂表面碱性位的分布有关. 因此, 采用尿素回流处理均相沉淀法制备的Cu/ZnO/Al2O3催化剂的甲醇收率最高.
关键词： CO2加氢; Cu/ZnO/Al2O3催化剂; 层状结构化合物; 甲醇; 尿素水解
肖硕1,2, 高鹏2, 杨海艳2, 夏林2, 张建明2, 陈志文1, 王慧2 . 层状Cu/ZnO/Al2O3催化剂的制备及其催化CO2加氢合成甲醇的性能[J]. 上海大学学报(自然科学版), 2016 , 22(2) : 218 -230 . DOI: 10.3969/j.issn.1007-2861.2015.05.019
Layered Cu/ZnO/Al2O3 catalysts were prepared with ahomogeneous precipitation method using urea hydrolysis. The mixed oxides were then obtained by the calcination and reduction of precursors and tested for methanol synthesis from CO2 hydrogenation. The prepared materials were characterized by X-ray diffraction (XRD), thermogravimetric(TG), scanning electron microscope (SEM), X-ray fluorescence (XRF), BET, H2-temperature program reduction (H2-TPR), N2O chemisorption, and CO2-temperature program desorption (CO2-TPD) techniques. Compared with the catalysts prepared by conventional co-precipitation method, the crystallinity degree of precursors, the BET specific surface area and dispersion of copper were increased with ahomogeneous precipitation method. This improvement was significant with reflux treatment during the homogeneous precipitation process. Evaluation of these catalysts for CO2 hydrogenation to methanol revealed that the CO2 conversion increased with increase of Cu specific surface area, and methanol selectivity was related to the proportion of strongly basic sites. Therefore, the maximum methanol yield was obtained over the Cu/ZnO/Al2O3 catalyst prepared using ahomogeneous precipitation method with reflux treatment.
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