One-Step Electrodeposition of Ternary Metal Sulfide Composite Nanorod Arrays as a Self-Supported Electrocatalyst for the Hydrogen Evolution Reaction

In this study, a self-supported material with a unique ternary metal sulfide nanorod array structure was fabricated in situ on copper foam via a facile one-step electrodeposition approach ((NiCo-Cu)S_x/CF). The electrochemically driven rapid generation of abundant S^2- ions from thiourea accelerates their combination with Ni²⁺ and Co²⁺, resulting in a catalytically enriched surface on the nanorod array. The high-density nanorod arrays provide maximally accessible active sites, thereby enhancing the hydrogen evolution reaction (HER). The in situ grown self-supported structure effectively eliminates the need for binders (common in conventional catalysts), avoids additional interfacial resistance, and ensures long-term stability during electrocatalytic operation. The synergistic interactions among the metal components (Ni, Co, and Cu) optimize the local electronic environment, creating favorable conditions for catalytic hydrogen evolution. The experimental results demonstrate that the ternary metal sulfide nanocomposite (denoted as (NiCo-Cu)S_x/CF) exhibits superior hydrogen evolution reaction performance compared to its binary counterparts. Remarkably, the catalyst required only 42 and 161 mV overpotential to deliver 10 mA·cm^-2 and 100 mA·cm^-2 current densities in 1 M KOH, respectively, with 100 h operational stability. This work provides a viable strategy for developing self-supported ternary non-noble metal catalysts for energy conversion applications.