Highly Ordered Pd/CeO x Inverse Opals for Alkaline Hydrogen Oxidation

Palladium supported on ceria (Pd/CeOx) has recently emerged as a promising electrocatalyst for the alkaline hydrogen oxidation reaction (HOR) in anion exchange membrane fuel cells. It has been proposed that CeOx provides OH spillover and modulates Pd-H binding, enhancing the reaction kinetics at the key Pd-Ce interface. Herein, we report a method to maximise the Pd-Ce interfacial area (Pd-O-Ce species) by synthesising highly ordered Pd/CeOx inverse opals (IOs) with tunable pore sizes (20-250 nm) directly on glassy carbon electrodes. The resulting IOs exhibit highly ordered pore networks which could be scaled down to the mesoporous regime (