Epitaxial interface stabilizing iridium dioxide toward the oxygen evolution reaction under high working potentials

Proton exchange membrane water electrolyzer (PEMWE) driven by renewable electricity is a promising technique toward green hydrogen production, but the corrosive environment and high working potential pose severe challenges for developing advanced electrocatalysts for the oxygen evolution reaction (OER). Although Ir-based materials possess relatively balanced activity and stability for the OER, their dissolution behavior cannot be neglected, in particular under high working potentials. In this work, iridium dioxide (IrO2) nanoparticles (NPs) were anchored on the surface of exfoliated h-boron nitride (BN) nanosheets (NSs) toward the OER reaction in acid media. Highly active Ir(V) species were stabilized by the epitaxial interface between IrO2 and h-BN, and therefore the IrO2/BN delivered stable performance at increased working potentials, while the activity of bare IrO2 NPs without h-BN support decreased rapidly. Also, the smaller lattice spacing of h-BN induced compressive strain for IrO2, resulting in improved activity. Our results demonstrate the feasibility of stabilizing highly active Ir(V) species for the OER in acid media by constructing robust interface and provide new possibilities toward designing advanced heterostructured electrocatalysts.