A novel Ir/CeO2–C nanoparticle electrocatalyst for the hydrogen oxidation reaction of alkaline anion exchange membrane fuel cells

Abstract

Alkaline anion exchange membrane fuel cells have faster kinetics for the oxygen reduction reaction (ORR) than proton exchange membrane fuel cells; however, the hydrogen oxidation reaction (HOR) at anodes with precious metals is more sluggish under alkaline conditions than that under acidic conditions, which hinders the further development of fuel cells. Herein, a novel catalyst, iridium nanoparticle-supported ceria–carbon black (10% Ir/CeO₂–C), was developed for use in the hydrogen oxidation reaction (HOR) under basic conditions. Cyclic voltammetry reveals that the electrochemical surface area of 10% Ir/CeO₂–C is 1.5 times that of 10% Ir/C. The RDE measurement suggests that the exchange current density of 10% Ir/CeO₂–C is 2.4 times that of 10% Ir/C, and the mass activity and specific activity of 10% Ir/CeO₂–C for HOR are greater than those of 10% Ir/C by 2.8 fold and 1.8 fold, respectively. The effective prevention of the agglomeration of the highly dispersed Ir nanoparticles could be ascribed to the strong metal–support interaction between Ir and CeO₂, and the promoted electrocatalytic activity would benefit from the oxophilic effect due to the higher oxygen storage-release capacity of ceria. Thus, 10% Ir/CeO₂–C would be a good candidate for use at the anode of alkaline anion exchange membrane fuel cells.