加料方式对CuO/ZnO/Al2O3系催化剂前驱体性质的影响

用XRD、TG-DTG、TPR技术研究了不同加料方式对CuO/ZnO/Al2O3系催化剂前驱体物相组成及其结晶情况的影响，用加压微反装置考察了催化剂合成甲醇反应活性。结果表明, 加料方式对Cu2+形成的中间化合物的物相组成及结晶度影响显著,对Zn2+及Al3+的沉淀物相的影响很小。不同加料方式对催化剂前驱体物相组成及催化剂性能的影响主要是形成的初始前驱体中Cu的物相及结晶度不同。正加法主要形成Cu2(OH)3NO3,并流法主要形成无定形Cu2CO3(OH)2,后者与Zn5(CO3)2(OH)6相互作用转化为(Cu,Zn)2CO3(OH)2和（Cu,Zn）5(CO3)2(OH)6，由它们分解形成的CuO-ZnO固溶体是合成甲醇反应的活性相。并流法能最大程度的形成CuO-ZnO固溶体，有利于CuO粒子的细化，其催化活性较好。

Influence of precipitation method on the properties of precursors of CuO/ZnO/Al2O3 catalysts

The influence of precipitation method on the precursors of CuO/ZnO/Al_2O_3 catalysts were studied by X-ray Diffraction, Thermogravimetry-Differential Thermogravimetry and Temperature Programmed Reduction techniques. The catalytic activity of the catalysts for methanol synthesis was tested using a differential fixed-bed reactor. It is found that the feeding method has strong influence on the Cu precursors in CuO/ZnO/Al_2O_3 catalyst. In case of base to salt, the initial precipitate was crystal Cu_2(OH)_3NO_3; while in the case of co-current, the initial phase was mainly amorphous Cu_2CO_3(OH)_2. The feed method has no effect on the initial phase composition and crystallinity of Zn-precursor and Zn_5(CO_3)_2(OH)_6 was the unique phase in the precursors. The phases of (Cu, Zn)_2CO_3(OH)_2 and (Cu, Zn)_5(CO_3)_2(OH)_6 in the precursors of the catalyst were produced from the substitution of Cu_2CO_3(OH)_2 (amorphous) and Zn_5(CO_3)_2(OH)_6. The activity of the catalyst was in the order of co-current>salt to base >base to salt.