Constructing a polycrystalline hybrid ternary CuS/Co3O4 with supported graphitic nitride electrocatalyst for bifunctional water splitting reactions

Abstract

The development of low-cost, durable, and highly efficient bifunctional electrocatalysts for water splitting across various media is essential for clean energy production. Herein, we synthesize a first of its kind polycrystalline ternary CuS/Co₃O₄@g-C₃N₄ bifunctional electrocatalyst, hydrothermally engineered to deliver exceptional performance for both hydrogen evolution (HER) and oxygen evolution reactions (OER). Metal encapsulated graphitic layered ternary composites are vital in water splitting as they offer enhanced catalytic performance, increased active sites, and improved stability. The obtained ternary catalyst achieves impressively low overpotentials of 191 mV and 213 mV at 10 mA cm⁻² (η₁₀), along with Tafel slopes of 78 and 89 mV dec⁻¹ in alkaline and acidic media, respectively. Operating under binder-free conditions, it demonstrates outstanding durability, sustaining activity for 40 and 60 hours for the HER and OER respectively. The unique hierarchical hollow structure significantly boosts the electroactive surface area, enhances charge transfer, and maximizes active site availability. This work highlights ternary composites as a promising candidate for next-generation electrocatalysts, paving the way for efficient, sustainable, and scalable water-splitting technologies.