Iridium-based electrocatalysts for the hydrogen oxidation reaction toward alkaline exchange membrane fuel cells

Abstract

Alkaline exchange membrane fuel cells (AEMFCs) hold great promise as highly efficient hydrogen energy conversion devices, largely due to the broad range of catalyst options available under alkaline conditions. However, the hydrogen oxidation reaction (HOR) at the anode exhibits significantly slower kinetics compared to proton exchange membrane fuel cells, which poses a challenge for achieving high performance. Iridium (Ir)-based catalysts present a compelling alternative to platinum (Pt)-based counterparts for the HOR in alkaline media due to their appropriate adsorption energy for both hydrogen and hydroxyl, alongside their superior CO tolerance. This review comprehensively summarizes recent advancements in the design strategies of advanced electrocatalysts for the alkaline HOR, including alloying effects, interface engineering, lattice strain, and phase engineering, focusing on their critical roles in modulating the electronic structure and coordination environments. Finally, the review discusses current challenges and offers perspectives on the future directions for improving the performance of Ir-based electrocatalysts. This review will guide future research in the development of high-performance Ir-based HOR electrocatalysts for AEMFCs.