Revealing the potential of vanadium doped Co9S8/CoO/NC electrocatalyst triggering HER and OER for alkaline water splitting

Abstract

Vanadium (V) doping in Co-based electrocatalysts is among apealling choices, crucial for demanding conductivity and intrinsic activity adjustment to mitigate the structural collapse to ensure their efficient participation in prevailing desirable bifunctional catalysis with exceeded hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, V-doping has coupled with hetero-interface generation in ZIF-67 derived hollow polyhedral structured cobalt sulfide (Co₉S₈) and cobalt oxide (CoO) hetero-particles with nitrogen-doped carbon (NC) armor (V-Co₉S₈/CoO/NC) via rationale fabrication strategy. Specifically, V incorporation renders multiple-valance transformation of Co²⁺/Co³⁺, considered a core factor in optimizing the adsorption energy of reaction intermediates to expedite the combined synergistic effect of Co₉S₈ and CoO heterostructure. Whereas, Co₉S₈/CoO hetero-interface formation further augments the rapid charge separation at the Co₉S₈/CoO interface. The wealthy interfacial exposed active sites contribute greatly to upgrading the electrocatalytic activity of V-Co₉S₈/CoO/NC. Besides, nitrogen-doped carbon (NC) buckles the structural fidelity of the catalyst to restrict the unavoidable corruption and dissolution, preserving its virtue of being long-term operationally durable. The prepared V-Co₉S₈/CoO/NC catalyst exhibits excellent performance for HER (106 mV) and OER (231 mV) at 10 mA cm^‐2 in an alkaline medium. The simulation results, performed using VASP, reveal significant charge redistribution and enhanced electronic conductivity at the Co₉S₈/CoO interface, highlighting the role of interfacial interactions in optimizing the heterostructure's properties for catalytic and electronic applications.