Nanostructured Ternary Ni–Co–V Multicomponent Oxide Electrocatalyst with Enhanced Electron Transport for Overall Water Splitting

Developing cost-effective, efficient electrocatalysts for clean hydrogen production has been successfully carried out using a heteroatom doping strategy which improved the electrochemical properties of materials. Herein, we report V-doping into NiCo-based precursors to get a multicomponent Ni–Co–V oxide catalyst by the hydrothermal-calcination process. The Ni, Co, and V components are coordinated strongly in CoNiV2O8 and have an integrated morphology of nanoflower-like arrays which increased its contact with water and exposed abundant active sites also owns multi channels to enhance the carrier transportation. Among the catalysts, CoNiV2O8-0.1, CoNiV2O8-0.3, CoNiV2O8-0.5, CoNiV2O8-0.7, and bare NiCo2O4V0, CoNiV2O8-0.5 exhibits superior activity by demanding a small overpotential (OER/HER) of 271/117 mV with a Tafel slope of 85/108 mV dec–1 and being stable for ∼100 h. The activation energy was calculated for electrolysis using CoNiV2O8-0.5 as 42.72 kJ/mol. The calculated integrated area of 4.60 × 10–5 AV with the number of active (5.730 × 1016) sites of CoNiV2O8-0.5 confirmed MOOH* formation. The superaerophobicity of CoNiV2O8-0.5 was substantiated by fast gas bubble evolution from the catalyst surface. The bifunctional electrolyzer with CoNiV2O8-0.5 (1.64 V) released vigorous gas bubbles and exhibited robust durability. Using CoNiV2O8-0.5, we have efficiently produced H2 with less power consumption of 751 LH2 kW h–1 than bare NiCo2O4V0 (782 LH2 kW h–1). The heteroatom doping strategy can be employed to design multifunctional catalysts with enhanced performances.