RuO2 nanoparticles anchored on g-C3N4 as an efficient bifunctional electrocatalyst for water splitting in acidic media

Abstract

The electrolysis of water, particularly proton exchange membrane (PEM) water electrolysis, holds great promise for hydrogen production in industry. However, the catalyst used in this process is prone to dissolution in acidic environments, making it imperative to develop cost-effective, highly efficient, and acid-stable electrocatalytic materials to overcome this challenge and enable large-scale application of PEM water electrolysis technology. Herein, we prepared ruthenium oxide (RuO₂)/graphitic carbon nitride (g-C₃N₄) composites (RuO₂/C₃N₄) via a combination of sol–gel and annealing methods. The g-C₃N₄ provides a large surface area, while RuO₂ is uniformly deposited on the g-C₃N₄ surface. The interaction between g-C₃N₄ and RuO₂ stabilizes the RuO₂ nanoparticles and enhances long-term water oxidation stability. This unique structure and the combined advantages of RuO₂ and g-C₃N₄ yield exceptional electrocatalytic activity toward both the oxygen evolution reaction (OER, 240 mV@10 mA cm⁻²) and the hydrogen evolution reaction (HER, 109 mV@10 mA cm⁻²), with excellent durability (over 28 h), and a cell voltage of 1.607 V at 10 mA cm⁻² when used in an RuO₂/C₃N₄||RuO₂/C₃N₄ electrolyzer. This study highlights the efficacy of the g-C₃N₄ support method in designing highly stable Ru-based OER electrocatalysts for efficient acidic water splitting.