Oxygen-vacancy-rich tungsten oxide boosted ultrasmall iridium nanoparticles for acidic oxygen evolution

Abstract

Proton exchange membrane water electrolysis (PEMWE) exhibits the superior benefits including high gas purity, high power density and wide variable loading but is still limited by the prohibitive cost and dearth of iridium (Ir)-based anode catalysts. Herein, we report a low-loading Ir-based catalyst with ultrasmall iridium nanoparticles (1.46 ± 0.01 nm) supported on oxygen-vacancy-rich tungsten oxide nanofibers (WO3-x) through electrospinning combined with surfactant-free microwave-assisted polyol reduction method for active acidic oxygen evolution reaction (OER). According to structural analysis and theoretical calculation, the charge transfer from W to Ir is induced by the strong electronic interaction at the Ir and WO3-x interface, thereby raising the electron density surrounding the Ir sites and favoring to boost OER activity. The resultant Ir@WO3-x exhibits an excellent overpotential of ca. 276 mV@10 mA cm−2 and remarkable durability. This study offers a new path for promoting the activity and durability of electrocatalysts while minimizing the mass loading of Ir towards OER.