Effect of process variables on Pt/CeO2 catalyst behaviour for the PROX reaction

A Pt/CeO2 catalyst has been evaluated for CO oxidation, both in the absence of H2 and in H2-rich feedstreams. The catalyst shows high activity and selectivity at temperatures as low as 80 °C, what makes it a viable catalyst for the selective depletion of CO in the temperature range at which PEMFC operate. The effect of: oxygen excess during operation (λ)(λ), the presence of either CO2 (5%), H2O (5%) or both in the feedstream, and the spatial time, on catalyst activity and selectivity has been evaluated.A λλ value of at least 2.25 was required for achieving total CO conversion, which occurs in the temperature range of 80–100 °C, being the selectivity practically stable at 44%. The presence of CO2 slight activates the catalyst, while steam inhibits catalyst activity. Water gas shift reaction contribution to CO oxidation was checked to be negligible in the 25–200 °C range.