Reducing the production costs of clean energy carriers such as hydrogen through scalable water electrolysis is a potential solution for advancing the hydrogen economy. Among the various material candidates, our group demonstrated transition-metal-based materials with tunable electronic characteristics, various phases, and earth-abundance. Herein, electrochemical water oxidation using Cu₂Se–V₂O₅ as a non-precious metallic electrocatalyst via a hydrothermal approach is reported. The water-splitting performance of all the fabricated electrocatalysts was evaluated after direct growth on a stainless-steel substrate. The electrochemically tuned Cu₂Se–V₂O₅ catalyst exhibited a reduced overpotential of 128 mV and provided a reduced Tafel slope of 57 mV·dec^–1 to meet the maximum current density of 250 mA·cm^–2. The optimized strategy for interfacial coupling of the fabricated Cu₂Se–V₂O₅ catalyst resulted in a porous structure with accessible active sites, which enabled adsorption of the intermediates and afforded an effective charge transfer rate for promoting the oxygen evolution reaction. Furthermore, the combined effect of the catalyst components provided long-term stability for over 110 h in an alkaline solution, which makes the catalyst promising for large-scale practical applications. The aforementioned advantages of the composite catalyst overcome the limitations of low conductivity, agglomeration, and poor stability of the pure catalysts (Cu₂Se and V₂O₅).