Reactant adsorption modulation by Fe and K in Pt catalyst for highly effective CO preferential oxidation in practical conditions

Abstract

Developing efficient and stable catalysts for preferential oxidation of CO (CO-PROX) within a wide temperature window is significant for the industrial hydrogen resource purification process. Herein, dual promoters of Fe and K were deliberately introduced to the mordenite supported Pt catalyst for optimizing the adsorption behaviors of reactants in CO-PROX. The optimal 1Pt0.1 K/Fe-MOR catalyst can achieve 100% CO conversion and 60–70% CO2 selectivity (the ratio of CO/O2 is 1:1) under the realistic application temperature range (130–200 °C), and remains catalytically stable during 65 h testing at 140 °C. A combination of detailed characterizations and density functional theory (DFT) simulations show that Fe species can avoid the co-adsorption of O2 on the Pt sites by providing more oxygen vacancy to activate O2, while K species will further enhance the adsorption of CO and repulse the adsorption of H2 on Pt surface. Therefore, the optimized adsorption of CO, O2 and H2 results in a total CO conversion and high CO2 selectivity in high temperature range.