Preferential CO oxidation over Pt–SnO2/Al2O3 in hydrogen rich streams containing CO2 and H2O (CO removal from H2 with PROX)

The effects of reaction gases including CO₂ and H₂O and temperature on the selective low-temperature oxidation of CO were studied in hydrogen rich streams using a flow micro-reactor packed with a Pt–SnO₂/Al₂O₃ sol–gel catalyst that was initially designed and optimized for operation in the absence of CO₂ and H₂O. 100% CO conversion was achieved over the 1 wt% Pt–3 wt% SnO₂/Al₂O₃ catalyst at 110 °C using a feed composition of 1.0% CO, 1.5% O₂, 25% CO₂, 10% H₂O, 58% H₂ and He as balance at a space velocity of 24,000 cm³/(g h). CO₂ in the feed was found to decrease CO conversion significantly while the presence of H₂O in the feed increased CO conversion, balancing the effect of CO₂.