Surface and Interface Modulation of V₂O₅/Ni(OH)₂ Nanomaterials for Enhanced Alkaline Water Splitting

To optimize the electrocatalytic reaction process through the synergistic effects of V and Ni, this study employed a two-step hydrothermal method to successfully construct a V₂O₅ composite structure grown on a Ni(OH)₂ substrate (denoted V₂O₅/Ni(OH)₂-2). Electrochemical evaluation revealed that this catalyst exhibits efficient bifunctional activity in 1.0 M KOH electrolyte. For the hydrogen evolution reaction (HER), it requires a mere 89.6 mV overpotential to achieve a current density of -10 mA cm^-2. The catalyst also demonstrates excellent performance in the oxygen evolution reaction (OER), demanding only 198 mV overpotential to drive a current density of 10 mA cm^-2, while maintaining low overpotential increases even at high current densities. Furthermore, it exhibits outstanding long-term stability during a 12 h continuous test. When assembled as a dual-electrode overall water splitting device, the system requires a voltage of only 2.82 V to drive a high current density of 100 mA cm^-2, showcasing its significant potential for practical applications.