PROX reaction of CO in H2/H2O/CO2 Water–Gas Shift (WGS) feedstocks over Cu–Mn/Al2O3 and Cu–Ni/Al2O3 catalysts for fuel cell applications

Catalytic conversion performance of the γ-Al2O3-supported Cu-, Mn- and Ni-based materials for the selective preferential oxidation of CO was investigated. The influence of CO2 and H2O in the reactor feed gas on activity and selectivity was lastly investigated for copper bimetallic catalysts containing manganese and nickel. Cu/Al2O3 proved to be optimal among the monometallic examined. It was observed that even in the absence of H2, CO was effectively converted. Upon H2 presence, a fraction of oxygen is utilized for the latter, which results in the decrease of CO turnover. Cu–Mn/Al2O3 surpassed other single and mixed metal oxide catalysts which could be due to a combination of surface desorption capacity and redox properties. The oxygen storage capacities (OSC) were in the order of Cu–Mn/Al2O3 > Cu–Ni/Al2O3 > Cu/Al2O3 > Mn/Al2O3 > Ni/Al2O3, in an agreement with reactivity. The efficiency at low process temperatures was enhanced by adding H2O vapors, nonetheless, decreased at high-end range due to the reverse water–gas shift (RWGS). Also, the rate of CO conversion was high utilizing Cu–Mn/Al2O3; furthermore, even upon applying H2O and CO2. CO2 notably affected CO conversion, and ultimately, decreased the activity, which, conversely, remained stable upon time-on-stream.