Pd/C-CeO2 anode catalyst for high performance platinum free anion exchange membrane fuel cells

One of the biggest obstacles to the diffusion of fuel cells is their cost, a large part of which is due to platinum (Pt) electrocatalysts. Complete removal of Pt is a difficult if not impossible task for proton exchange membrane fuel cells (PEM-FCs). The Anion Exchange Membrane Fuel Cell > (AEM-FC) has long been proposed as a solution as non-Pt metals may be employed. Despite this, few examples of Pt free AEM-FCs have been demonstrated with modest power output. The main obstacle preventing the realization of a high power density Pt free AEM-FC is sluggish hydrogen oxidation (HOR) kinetics of the anode catalyst. In this presentation we describe a Pt free AEM-FC that employs a mixed carbon-CeO2 supported palladium (Pd) anode catalyst that exhibits enhanced kinetics for the HOR. AEM-FC tests run on dry H2 and pure air show peak power densities of more than 500 mW cm-2. We have investigated the origin of this remarkable performance using cyclic voltammetry (CV), HR-TEM/STEM as well as XAS. This analysis shows the improvement is due to a strong interaction between Pd and CeO2. This talk describes a careful morphological analysis that attests to a fine dispersion of the Pd nanoparticles accumulated mostly on the ceria part of the catalyst. Such a structure helps to weaken the Pd-H bonds and assists in supplying OHad from oxophilic CeO2 to the Pd-Had (HOR reaction sites), thus accelerating the overall HOR.