Lewis acidic W/WO3−x heterostructure-coupled Ir catalysts with low Ir loading for efficient pH-universal water splitting

Abstract

In this study, we reported three tungsten compound-supported Ir catalysts with different reduction degrees, Ir–WO_3−x, Ir–W/WO_3−x, and Ir–W, as pH-universal water splitting catalysts. The Ir–W/WO_3−x catalyst, with an optimized local acidic microenvironment for Ir sites under neutral conditions, exhibited the lowest HER overpotential of 60 mV in 1.0 M PBS, while Ir–W achieved the lowest OER overpotential of 336 mV in 1.0 M PBS. Using the Ir–W‖Ir–W configuration, a low cell voltage of 1.593 V at 10 mA cm⁻² was achieved in a neutral water electrolyzer.