科研之友
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摘要
Gold-glutathione complex catalysts for acetylene hydrochlorination were prepared at different pH values. Coal-based columnar carbon, HAuCl4.4H(2)O and glutathione (GSH) were added as the carrier, the precursor and the protective/reductive agent, respectively. The catalysts were characterized by Fourier transform infrared spectroscopy, ultraviolet spectrum, N-2 adsorption/desorption, thermogravimetric analysis, temperature-programmed reduction/desorption, powder X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The highest activity is obtained over the Au-1-GSH3/AC (pH 8.3) catalyst with the acetylene conversion of 82%, under the conditions of 170 degrees C and the C2H2 gas hourly space velocity (GHSV) of 360 h(-1). It is indicated that the addition of GSH can result in the reduction of Au3+ to Au+ during the catalysts preparation process, the species of Au+ and Au-0 coexist in the fresh Au-1-GSH3/AC catalysts, with the individual content close to 50%. Compared with fresh Au/AC catalyst comprised of Au3+ and Au-0, it is illustrated that the presence of Au+ plays an important role in enhancing the catalytic activity. Adjusting the pH of the catalyst to a suitable value can make more active species disperse well on the catalysts, inhibit coke deposition and enhance the adsorption ability of reactants.
