In Situ Diffuse Reflectance Spectroscopy of Supported Chromium Oxide Catalysts: Kinetics of the Reduction Process with Carbon Monoxide

摘要

In situ diffuse reflectance spectra of supported chromium oxide catalysts are investigated for the first time atudelevated temperatures under controlled reaction conditions using a specially designed diffuse reflectionudattachment. The obtained results are compared and discussed with those obtained by the classical diffuseudreflectance spectroscopy technique. A novel method for studying the reduction kinetics of supported transitionudmetal oxides is proposed. In the case of Cr(VI), the reduction is faster on silica than on alumina. A kineticudmodel is developed to explain the kinetics. It consists of the activation of CO by adsorption followed by theudreduction of Cr^6+ with formation of surface carboxylates.