A low Ir loading Inverse opal self-supporting electrode for efficient and durable PEM water electrolysis

Abstract

Reducing the expenditure on noble Ir is crucial for the industrial application of proton exchange membrane water electrolysis (PEMWE). In this work, an ordered array electrode prepared by the electrodeposition of Ru and Ir at Inverse Opal (IO) structure decorated Ti felt (Ir@RuO₂ IO/Ti felt-300 nm) is provided as the anode of PEMWE, which exhibited an enlarged electrochemically active surface area and a state-of-the-art Ir loading of 0.0841 mg _Ir cm⁻². Thus, the electrolyzer fabricated by the as-prepared electrode reached large current densities of 1 A cm⁻² and 3 A cm⁻² at 1.64 V and 2.02 V during PEMWE, respectively. Furthermore, enabled by the Ir@RuO₂ core-shell structure which can modulate the electronic microenvironment and prevent excessive oxidation dissolution of active metal sites, the PEMWE electrolyzer presented enhanced durability and drove the constant cell voltage PEMWE at 1 A cm⁻² for 250 h. This work offers a cost-effective strategy to minimize Ir reliance while advancing PEMWE efficiency and longevity.