Double-Transition-Metal MXene-CoS₂ Hybrid Electrocatalysts: A New Avenue for Alkaline Hydrogen Evolution

Abstract

The global demand for hydrogen (H₂) production via electrolysis is rapidly increasing, necessitating the development of low-cost and high-performance electrocatalysts. Herein, we report the synthesis of a double-transition-metal (DTM) MXene, molybdenum titanium carbide (Mo₂Ti₂C₃T_x), using a non-hydrofluoric (HF) acid-based etchant, followed by the incorporation of cobalt sulfide (CoS₂) nanoparticles through a hydrothermal process. The optimized Mo₂Ti₂C₃T_x@CoS₂ composite demonstrated excellent electrocatalytic activity for the hydrogen evolution reaction (HER) in alkaline media, achieving a low overpotential of 281 mV at 10 mA/cm², a Tafel slope of 79 mV/dec, and a high electrochemical active surface area (ECSA) of 375 cm². Theoretical calculations further validated the efficiency of the material, and its application in a real-time anion exchange membrane (AEM) electrolyzer confirmed its stability and high H₂ production rate. These findings highlight Mo₂Ti₂C₃T_x@CoS₂ as a promising noble-metal-free electrocatalyst for sustainable H₂ production and electrochemical energy conversion.

Keywords

2D MXene / clean energy / cobalt sulfide / electrochemical water splitting / H₂ production

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