Pairing Ru-doped NiCo-layered double hydroxides and selenide derivatives as self-supporting electrocatalysts for alkaline overall water splitting

Abstract

The pursuit of a catalyst exhibiting exceptional efficacy and an optimal cost−performance ratio is currently a prominent research focus. Herein, Ru-NiCo LDH/NF-4 (4 represents 4 mg mL⁻¹ RuCl₃·xH₂O solution) is prepared by impregnating NiCo layered double hydroxides (NiCo LDH) grown on nickel foam (NF) with RuCl₃·xH₂O solution. Ru-NiSe₂/CoSe/NF-4 is prepared by selenization of Ru-NiCo LDH/NF-4. Benefiting from the three-dimensional flower-like nanosheet arrays, the synergistic effect between Ru and non-precious metal materials and the change in Ru's electron valence state, Ru-NiCo LDH/NF-4 and Ru-NiSe₂/CoSe/NF-4 exhibit low HER and OER activity, achieving overpotentials of 45 mV and 238 mV, respectively, with a current density of 10 mA cm⁻² in 1.0 M KOH. Furthermore, when utilizing Ru-NiCo LDH/NF-4 as the cathode electrode and Ru-NiSe₂/CoSe/NF-4 as the anode electrode, a voltage of 1.53 V is required to achieve overall water splitting at a current density of 10 mA cm⁻², gaining exceptional stability for over 300 hours in 1.0 M KOH. This work presents a novel approach for integrating precious metals and non-precious metal materials to reduce costs and optimize performance, offering a fresh perspective on novel combinations for water electrolysis.