Polyoxometalate-mediated growth of O-SnS@Cu2S heteronanosheets for high-performance oxygen and hydrogen evolution reactions

Abstract

To properly exploit undepleted sources of energy through energy conversion devices using water splitting reactions, there is a need for cost-effective, easily accessible, and long-lasting materials that are capable of performing bifunctional activity like hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In this study, oxygen incorporation into SnS@Cu₂S (O-SnS@Cu₂S) heteronanosheets was architecture on Nickel foam utilizing polyoxometalate as bimetal precursors, and then this material exhibited superior activity, requiring only a small overpotential to generate high current densities compared to individual O-SnS and O-Cu₂S arrays for the electrocatalytic HER activity. The Tafel slopes (26 mV dec⁻¹) and electrochemical impedance spectroscopy (EIS) (R_ct = 1.2 Ω), further confirmed the favorable kinetics and conductivity of the O-SnS@Cu₂S array. When compared to the O-Cu₂S and O-SnS nanosheet arrays, the bimetal sulphides O-SnS@Cu₂S array had much lower overpotentials, requiring only 170 mV and 232 mV, respectively, to achieve a current density of 10 mA cm⁻² in an alkaline solution for HER and OER. The O-SnS@Cu₂S nanosheet array outperformed SnS and Cu₂S, requiring lower overpotentials to achieve high current densities. The smaller value of Tafel slopes (23 mV dec⁻¹ for O-SnS@Cu₂S) indicated improved kinetics, and EIS demonstrated a lower polarization resistance (R_ct = 0.2 Ω) for the O-SnS@Cu₂S array. Importantly, the O-SnS@Cu₂S array exhibited remarkable stability in alkaline electrolyte cycling experiments, making it an outstanding material for practical applications in energy conversion devices. This research proposes a feasible technique for the development of efficient and stable bifunctional bimetal-sulfide electrocatalysts with enormous potential for use in renewable energy.