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采用等容浸渍法制备了三种类型的Cu/SiO_2,催化剂(铜担载量都为3.3Wt%).将其制备因素与XRD、SEM、XPS等表征手段所得结果相关联,得出氨具有分散硅胶表面铜组分的作用、有无氨介入催化剂制备过程可导致截然不同的表面CuO分散状态.有氨介入时所得催化剂表面孤立Cu~(2+)(二硅氧基钳合—Cu~(2+)与具有一定分散程度的CuO共存、氨介入方式及所用铜盐不同,二种状态的铜组分在载体表面所占的比例不同.用硝酸铜为原料,先浸铜盐后浸氨的方式所得催化剂表面绝大部分为孤立Cu~(2+);而浸铜盐后不浸氨的催化剂表面绝大部分为CuO.在制得的5个催化剂中,表面上明显有CuO存在的4个催化剂,CuO似乎都分布于载体外表面,即形成近似于“蛋壳形”的分布.
Three kinds of Cu / SiO 2 catalysts were prepared by isostatic impregnation method with the copper loading of 3.3Wt% .According to the results of XRD, SEM, XPS and other characterization methods, Disperse the role of the copper component on the surface of the silica gel, with or without ammonia intervening catalyst preparation process can lead to a completely different state of the surface CuO dispersion state with ammonia intervention catalyst surface isolated Cu ~ (2 +) (disilicoxy- (2+) coexist with CuO with a certain extent of dispersion. The way of ammonia intervention and the copper salt used are different, and the proportions of copper components in the two states are different on the surface of the support. Using copper nitrate as raw material, Ammonia way most of the surface of the catalyst is isolated Cu ~ (2 +); and Cu impregnated with copper salt is not the surface of the catalyst for the vast majority of CuO in the five catalysts obtained, the surface is obviously CuO Of the four catalysts, CuO seems to be distributed on the outer surface of the carrier, that is to form a distribution similar to the “egg shell shape.”