Promotion of Pt/γ-Al2O3 by New Pretreatment for Low-Temperature Preferential Oxidation of CO in H2 for PEM Fuel Cells

The hydrogen-rich reformate used as a feed to polymer electrolyte fuel cells (PEFC) must contain less than 10 ppm CO since it poisons the Pt anode. The concentration of CO leaving the water–gas shift reactor is typically around 1 mol%, which is set by thermodynamic equilibrium. One method to remove the CO is by preferential oxidation (PROX) using O2 over a (typically) Pt catalyst while minimizing the amount of H2 oxidized. The activity and selectivity of this reaction were improved by a new pretreatment method for a 5 wt% Pt/γ-Al2O3 catalyst. The pretreatment involved saturating the reduced catalyst with water and allowing it to vaporize during reduction. The improvement is attributed to a reduction in size of the metallic Pt particles as measured by XRD and TEM.