Ru/Ir on Fe₂O₃ as an Efficient Catalyst for Preferential Oxidation of CO towards Hydrogen Purification

Preferential oxidation of CO is an effective process to clean up CO in hydrogen for proton exchange membrane fuel cells (PEMFCs). Herein, we synthesis a highly efficient catalyst for CO-PROX through the deposition of Ru/Ir nanojunctions on Fe₂O₃ nanoparticles. The as-prepared catalyst shows 90% CO conversion at 80 °C within the working temperature of PEMFCs and the total CO conversion in the temperature range of 140 °C to 160 °C under gas flow velocity of 36000 mL·g⁻¹·h⁻¹ while maintaining good stability for 24 h. Density functional theory calculations reveal that the substrate Fe₂O₃ not only serves as a source of lattice oxygen atoms for the catalytic process but also acts as an electron acceptor from Ru/Ir, thereby regulating its valence state. This regulation is beneficial for the adsorption of reaction intermediates and reduces the activation energy of PROX.