Thermally modulated RuO2/MoOx heterostructures for high-efficiency electrocatalytic oxidation reactions

Abstract

As ever-increasing global energy demands intersect with heightened environmental awareness, next-generation sustainable power generation methods have become a focal point of extensive research. Hydrogen fuel has emerged as a promising carbon-neutral energy carrier, with water electrolysis-based hydrogen synthesis drawing particular interest owing to its environmental benignity and zero-emission operation. Nevertheless, the inherent thermodynamic limitations and sluggish kinetics of the anode's oxygen evolution process (OER) present substantial energy efficiency barriers that require innovative electrocatalyst solutions. Ruthenium-based catalysts are highly favored for their high activity and low cost, yet their tendency to aggregate during synthesis compromises catalytic performance. This study presents a method for preparing RuO₂/MoO_x heterostructure catalysts, where precise control of molybdenum oxidation states through thermal modulation significantly enhances OER catalytic activity and stability. In alkaline media, the RuO₂/MoO_x catalyst achieves a low overpotential of 212 mV and exhibits a Tafel slope of 70.8 mV·dec⁻¹. Furthermore, the 72-h stability test in alkaline solution confirms the material's exceptional durability. Additionally, the catalyst demonstrates superior performance in urea oxidation (UOR) and ammonia oxidation reactions. This work provides a scalable strategy for developing high-performance and stable RuO₂/MoO_x based electrocatalysts.