Preparation of CuO/γ-Al_2O_3 Catalysts by Impregnationin Supercritical CO_2

摘要

CuO/γ-Al_2O_3 catalysts were prepared by supercritical CO_2 (SC-CO_2) impregnation method. The preparation was carried out in SC-CO_2 with Cu(NO_3)_2 as precursor, methanol as assistant solvent, and γ-Al_2O_3 as support. The effects of impregnation parameters such as temperature and pressure of SC-CO_2, impregnation time, ratio of precursor to support, and amount of assistant solvent on catalyst preparation were investigated. The as-prepared catalysts were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis and compared to that prepared by the conventional impregnation method. The SC-CO_2 impregnation method provided higher adsorption rate, larger adsorption quantity, more homogeneous dispersion of precursor, and stronger interaction between precursor and support. The catalytic degradation of methylene blue (MB) was used as probe reaction to estimate the catalytic activity of two catalysts prepared by two methods. The catalyst prepared by SC-CO_2 impregnation method exhibits significantly improved catalytic activity. These results show that the inorganic metallic reagents as precursor with assistant solvent can be used as an alternative for the organometallic precursors in SC-CO_2 impregnation method.