论文部分内容阅读
通过柠檬酸辅助固相研磨法制备铜基催化剂,采用XRD、TPR、TG-DSC、SEM、BET、TEM、XPS、CO_2-TPD等手段对催化剂性能进行表征.结果表明室温固相研磨的前驱体在惰性气体N_2中焙烧使体系中的CuO绝大部分被原位还原成Cu~0,不需外加H_2还原,直接制得了C/I-Cu/ZnO催化剂,催化剂具有中孔.利用高压固定床连续反应装置对催化剂活性进行了评价,结果表明,柠檬酸用量、前驱体焙烧温度、焙烧升温速率等条件对催化剂活性产生影响,当C_6H_8O_7/(Cu+Zn)摩尔比为1.2/1并Cu/Zn摩尔比1/1,前驱体在N_2中以3 K·min~(-1)升温速率于623 K焙烧3 h,制得的C/I-Cu/ZnO催化剂比表面积最大,Cu~0粒径最小,在CO_2加氢合成甲醇反应中表现出最佳的活性,CO_2转化率、甲醇选择性和产率分别达到了28.28%、74.29%和21.01%.与外加H_2还原的C/H-Cu/ZnO催化剂相比,原位还原C/I-Cu/ZnO催化剂比表面积较大,Cu~0的粒径较小,活性较高.
The catalysts were characterized by XRD, TPR, TG-DSC, SEM, BET, TEM, XPS and CO_2-TPD, respectively. The results showed that the solid state grinding precursors In the inert gas N 2 roasting the most of the CuO system was reduced to Cu ~ 0 in situ, without additional H_2 reduction, prepared directly C / I-Cu / ZnO catalyst, the catalyst has a mesoporous. Using high-pressure fixed bed The results showed that the amount of citric acid, the precursor calcination temperature and the calcination temperature increased the activity of the catalyst. When the mole ratio of C 6 H 8 O 7 / (Cu + Zn) was 1.2 / 1 and Cu / Zn molar ratio 1/1. The precursor was calcined at 623 K for 3 h at a heating rate of 3 K · min ~ (-1) in N 2. The C / I-Cu / ZnO catalyst had the largest specific surface area and Cu ~ The smallest diameter, the best activity in the reaction of CO_2 hydrogenation methanol, the CO 2 conversion, methanol selectivity and yield reached 28.28%, 74.29% and 21.01%, respectively.Compared with C / H-Cu Compared with ZnO / C catalyst, the specific surface area of C / I-Cu / ZnO catalyst was larger than that of Cu / ZnO catalyst.