Surface Structure and Catalytic Properties of Cu/SiO2 Catalysts Prepared by Different Methods

The silica supported copper catalysts were prepared via impregnation (IM), solgel (SG) and deposition precipitation (DP) methods. The catalysts were characterized by XRD, H2-TPR, NH3-TPD, H2-N2O titration, XPS, BET and EPR techniques. The results indicated that two copper species, Cu2+ and Cu0 exist on the surface of SG catalyst; how ever, only Cu0 species could be found on the surface of reduced IM and DP catalysts, and the dispersion of Cu0 on IM catalyst was better than that on DP catalyst. According to the reaction results, Cu0 should be the active sites for dehydrogenation of cyclohexanol. Cu2+ species on the surface of SG catalyst might be responsible for the dehydration of cyclohexanol. The residual Na was found on the surface of DP catalyst, which made the acidity decreas ing, and the Cu crystallite growing up easily.