Black titania (BT) incorporated carbon nitride (C₃N₄) nanoparticles; synthesized with imidazole and titania P-25 for the first time, without washing steps, was then loaded with 3 wt% of Ag₂O, Ag₂S, and CuO nanoarchitecture through a deposition hydrothermal route. The obtained electrocatalyst CuO/BT offers abundant active sites composed of TiO_2−x@TiO₂ interfaced with C₃N₄; that has been emphasized via various physicochemical techniques, besides the Cu⁺/Cu⁺⁺ moieties, thus providing an exceptional electrocatalytic performance (configured using CV, LSV, EIS, and ECSA) under both neutral (KCl, pH = 7) and dark conditions. The overall water electrolysis to produce 10 mA cm⁻² requires a potential of 1.7 V. This electrode exhibits a superior efficiency due to lowering Tafel slope values for HER (−38.96 mV dec⁻¹) and OER (102.2 mV dec⁻¹), surface oxidation layers due to Cu²⁺/Cu¹⁺, good conductivity, charge transfer facility, and high electrocatalytic surface area. This study provides a plausible route to construct the C₃N₄ heterostructure Ti₂O₃/Ti₃O₅ with multiple interfaces, which is considered a good candidate for water splitting.