2D/2D Heterojunction Interfaces of 1T-MoS2 and Ti3C2 MXene: Designing High-Performance Catalyst for the Hydrogen Evolution Reaction

Abstract Designing efficient electrocatalysts for the hydrogen evolution reaction (HER) is crucial for advancing sustainable energy technologies. In this study, a 2D/2D heterostructure composed of 1T-phase molybdenum disulfide (1T-MoS₂) and titanium carbide MXene (Ti₃C₂Tx, denoted as Ti₃C₂) is synthesized using a one-step hydrothermal method. The hybrid catalyst exhibits improved HER kinetics, demonstrated by a low overpotential of 248 mV at 10 mA cm⁻² and a Tafel slope of 55 mV dec⁻¹, indicating fast reaction kinetics and favorable charge transfer. The addition of tetramethylammonium ions (TMA⁺) induces interlayer expansion, increasing the 1T phase content to 89%. Incorporating only 1 % Ti₃C₂MXene suppresses oxidation and enhances stability. The composite demonstrates a large electrochemical surface area, high turnover frequency (TOF), and retains over 90% of its catalytic activity after extended electrolysis. This scalable approach offers a promising route to developing stable, efficient 2D electrocatalysts for hydrogen production.