Study of Ce-Pt/γ-Al2O3 for the selective oxidation of CO in H2 for application to PEFCs: Effect of gases

In order to supply pure hydrogen to proton exchange membrane (PEM) fuel cells and avoid CO poisoning, selective CO oxidation in H2 was studied over Ce-Pt/γ-Al2O3. Adding the Ce promoted the CO conversion and selectivity of Pt/γ-Al2O3 with changing loading weights of Pt and Ce, oxygen concentration, residence time, and the composition of gases (H2O, CO2, and N2). At 250 °C, adding H2O to the feed gas enhanced the CO conversion due to the water–gas shift reaction. While, adding CO2 to the feed gas suppressed the CO conversion due to the reversible water–gas shift reaction. In situ BET and XRD tests showed that well-dispersed metallic Pt particles (−2 nm) existed on the Ce oxide over the alumina support, which helps to supply oxygen to the Pt for a high activity of CO oxidation and selectivity.