Microstructure engineering of Co-MOF derived MoS2CoS2/CoSO4 composite: Synergistic effects and ionic distribution optimization for efficient hydrogen evolution

The development of cost-effective and high-performance electrocatalysts for the hydrogen evolution reaction (HER) is crucial for sustainable energy systems. Herein, we report a novel Co-MOF-derived MoS 2 CoS 2 /CoSO 4 composite on carbon cloth, synthesized through a controlled hydrothermal and thermal activation process. This catalyst achieves a low overpotential of 36 mV at 10 mA cm −2 and a Tafel slope of 36 mV dec −1 in 1 M KOH, rivaling commercial Pt/C. By managing the preparation temperature, we preserved the MOF structure’s integrity, maintaining a high specific surface area. Sulfurization at 450 °C enhanced electron transfer and prevented nanoparticle aggregation. The catalyst demonstrates remarkable stability over 175 h, attributed to the Co-Mo bimetallic synergy and in-situ composite formation, which optimize hydrogen adsorption and electron transfer. Importantly, we explored how sulfur source modulation affects active site formation and activity. Lower sulfur levels hinder CoS 2 formation, resulting in sparse sites and inferior performance, while optimal sulfur ensures dense composite growth. This study emphasizes the importance of local ionic dynamics in shaping catalyst microstructure and provides a universal method for designing non-precious metal electrocatalysts through ionic distribution engineering.