Copper catalysts prepared via microwave-heated polyol process for preferential oxidation of CO in H2-rich streams

The purposes of this study were to prepare a copper catalyst by the microwave-heated polyol (MP) process and subsequently to evaluate the feasibility of the preferential oxidation of CO (CO-PROX) in excess H₂. A CeO₂-TD support was firstly prepared by the thermal decomposition from Ce(NO₃)₃·6H₂O precursor. For comparison, commercial ceria (CeO₂-C) and activated carbon (AC) selected as support materials. Experimental results of CO-PROX indicated that the highest catalytic activity is achieved when the Cu/CeO₂-TD used as catalysts. Correlating to the characteristic results, it is found that the CeO₂-TD support prepared by the thermal decomposition has a large surface area and high mesoporosity; these properties contribute to the easy adsorption of pollutants and the effective dispersion of metal particles. Further investigation of feed composition found that Cu/CeO₂-TD catalysts possess 100% CO conversion even existence of CO₂ and H₂O in H₂-rich streams at 150 °C. Besides, a decrease in CO conversion was clearly observed above 175 °C for Cu/CeO₂-TD catalysts due to the reverse water gas shift reaction tending to reform CO from CO₂ and H₂.