Enhanced stability for preferential oxidation of CO in H2 under H2O and CO2 atmosphere through interaction between iridium and copper species

Abstract

Preferential oxidation of CO (CO-PROX) is one of the most investigated methods for reducing residual CO in H2-rich stream to acceptable level in proton exchange membrane fuel cells. However, development of catalyst with high stability under simulated practical conditions is still challenging. Herein, a series of CuxCe1-xO2 (x = 0, 0.05, 0.09, 0.17) supported Ir catalysts were prepared and 1 wt%Ir/Cu0.09Ce0.91O2 exhibited full conversion of CO in a wide temperature window (80–180 °C), excellent stability and resistance to CO2 and H2O poison. Characterization results reveal that the superior performance was mainly associated with the interaction between Ir and Cu species, which resulted in that the adsorbed H2O on Ir sites was activated to react with adsorbed CO on Cu sites to form easily decomposable bicarbonates and formate species instead of main intermediate of carbonates for 1 wt% Ir/CeO2 and Cu0.09Ce0.91O2. This work provides a new sight for developing high-performance heterogeneous catalysts.