Performance of Pt-Fe/mordenite monolithic catalysts for preferential oxidation of carbon monoxide in a reformate gas for PEFCs

Pt-Fe/mordenite catalysts coated on ceramic straight-channel monoliths were evaluated for the preferential oxidation of carbon monoxide (PROX) in hydrogen-rich gas streams. In a feed gas containing 1% CO, 1% O₂, with the balance H₂, CO conversion reached almost 100% at temperatures ranging from 100 to 130 °C, i.e., an outlet CO concentration of less than 10 ppm. Even in a synthetic reformate gas (1% CO, 1% O₂, 15% H₂O, 20% CO₂, balance H₂), the monolithic catalyst exhibited excellent activity, reducing the CO concentration to less than 100 ppm. In particular, under optimized conditions, an outlet CO concentration of less than 10 ppm was realized. This is the first report that has demonstrated that monolithic catalysts could achieve the 10-ppm target level at a low O₂/CO ratio and a high space velocity in a single-stage reactor. Excellent durability of the monolithic catalyst is expected, based on a lack of deterioration in performance during 500 h of operation.