关键词: 共沉淀法, 助剂, CuO-ZnO-Al2O3, CO2加氢, 甲醇

Abstract: CuO-ZnO-Al2O3 was modified by co-precipitation，using MgO，CaO as promoters. The effects of MgO，CaO on phase composition and catalyst structure were illuminated by using N2 adsorption-desorption，TG-DTG，XRD，H2-TPR and CO2-TPD techniques. The catalysts were tested in the synthesis of methanol from CO2 hydrogenation in a fixed-bed reactor. It indicated that the addition of CaO favored the formation of aurichalcite (Zn,Cu)5(CO3)2(OH)6 and malachite zinc (Cu,Zn)2CO3(OH)2 in the precursor of the catalyst. The more (Zn,Cu)5(CO3)2(OH)6 or (Cu,Zn)2CO3(OH)2 precursor possessed，more synergy，lower reduction temperature after calcination it exhibited，which improved the catalytic performance of catalyst modified by CaO. The promoter of MgO did not benefit the formation of aurichalcite (Zn,Cu)5(CO3)2(OH)6 and malachite zinc (Cu,Zn)2CO3(OH)2，which led to less active catalyst due to the weak synergetic effect between Cu and ZnO. On the other hand，the formation of MgO-CuO solid solutions reduced the activity of the catalyst，although the crystallite size of CuO，ZnO was decreased and the dispersion of Cu on the surface was enhanced. It was also found that the intensity and amount of basic sites on the catalyst surface were modulated by the promoter of MgO，CaO. The CaO-modified CuO-ZnO-Al2O3 catalyst possessed stronger basic sites than that of MgO-modified，which was accordance with the basic strength order of CaO and MgO.

Key words: co-precipitation, promoter, CuO-ZnO-Al2O3, hydrogenation of CO2, methanol