Co-Ce PROX Catalysts for Renewable, Climate-Independent, and Emission-Free “On-Board” Energy

Trace amounts of CO in H2-rich gas can poison Pt electrodes in proton-exchange-membrane fuel cells, necessitating selective CO removal. Preferential oxidation of CO (PROX) offers an efficient route to oxidize CO while preserving H2. Although noble-metal-based catalysts are widely used, their high cost has driven interest in non-precious alternatives. Co3O4–CeO2 catalysts have emerged as particularly promising due to their high activity and stability. Two series of Co–Ce/SiO2 catalysts were prepared via impregnation: in the first, Ce was introduced and calcined prior to Co deposition; in the second, Co and Ce nitrates were co-deposited from a mixed aqueous solution. The latter method enhances the interaction between Co3O4 and CeO2, increasing the availability of surface oxygen species. Stability tests on the most active sample demonstrated remarkable durability, maintaining near-complete CO conversion over 100 h on dry stream.