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

In this study, we reported three tungsten compound-supported Ir catalysts with different reduction degrees, Ir-WO3-x, Ir-W/WO3-x, and Ir-W, as pH-universal water splitting catalysts. The Ir-W/WO3-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 & Vert;Ir-W configuration, a low cell voltage of 1.593 V at 10 mA cm-2 was achieved in a neutral water electrolyzer.