A Route to Develop the Synergy Between CeO2 and CuO for Low Temperature CO Oxidation

Abstract

Highly active nano-composite oxide of cerium-copper was synthesized via physical grinding of respective metal oxides using mortar and pestle for the oxidation of carbon monoxide. The prepared oxides were characterized using X-ray diffraction (XRD), Thermal-gravimetric studies (TG), Infrared spectroscopy (IR), Scanning electron microscopy (SEM) and BET surface area. In addition, CO adsorption and surface reduction–oxidation property was studied through CO pulse titration, H2-TPR and O2-TPO to understand their surface sensitivity towards it. Among the tested catalysts, synergy interaction produced between cerium and copper oxides after grinding them using mortar and pestle leads to an excellent CO to CO2 conversion. High CO chemisorption and an enhanced redox property are the evidence for the synergy exhibited by CeO2–CuO composite catalyst. The grinding route helped in improving the CO oxidation by decreasing the active temperature region for the reaction showed a good correlation with high CO adsorption and increased oxygen mobility at lower temperature gradient over CeO2–CuO composite. Further, good reaction stability was also seen with the addition of moisture in the reaction mixture.