Exploring the bifunctional electrocatalytic activity of tin sulfide decorated manganese iron oxide in alkaline and urea contaminated water

Efficient, affordable, and stable electrocatalysts are pivotal for large-scale water splitting. Herein, we report an optimized decoration of tin sulfide (SnS) bundles on porous manganese ferrite (MnFe₂O₄) on nickel foam for enhancing the overall water splitting. This decoration yielded an interfacial Sn-O bond between MnFe₂O₄ and SnS, stabilized the structure, and provided optimistic adsorption energies for oxygen and hydrogen. The decorated electrode exhibited overpotentials of 383 mV for the oxygen evolution reaction (OER) and 127 mV for the hydrogen evolution reaction (HER) at 20 mA.cm⁻². Moreover, the decorated sample demonstrated reduced overpotentials of 272 mV and 75 mV (at 20 mA cm⁻²) for OER and HER in urea-contaminated water. The augmented double layer capacitance (C_dl) electrochemical surface area (ECSA) and X-ray photoelectron spectroscopy (XPS) studies of the decorated sample corroborated the enhanced performances and effectiveness of the SnS decoration. Furthermore, SnS-decorated MnFe₂O₄ showed outstanding performance in a two-cell configuration with a cell voltage of 1.69 V and 1.52 V (@10 mA cm⁻²) under alkaline KOH and urea (0.33 M) electrolyte, respectively. Further, the chronoamperometry and post-X-ray photoelectron spectroscopy studies demonstrated the stability and promising potential of this electrode for future non-noble metal-based bifunctional catalytic applications.