Nanostructured TernaryNi–Co–V MulticomponentOxide Electrocatalyst with Enhanced Electron Transport for OverallWater 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 L_H₂ kW h^–1 than bare NiCo₂O₄V₀ (782 L_H₂ kW h^–1). The heteroatom doping strategy can be employed to design multifunctional catalysts with enhanced performances.