Being a narrow band gap semiconductor, the photocatalytic activity of bare Ni 2 P is highly limited. However, a proper band gap tuning of Ni 2 P through effective composite formation furnishes a fruitful strategy for developing active photocatalytic materials. In this regard, the present work reports the application of an efficient photocatalytic ternary composite in the form of a coating formed from CoO/rGO and Ni 2 P. The simultaneous reduction of GO to rGO disperses crystalline CoO nanoparticles in it. The CoO-embedded rGO nanosheet can act as an efficient conducting material that helps to mediate the redox reactions in CoO and Ni 2 P. CoO/rGO enriches the catalytically active sites in the Ni 2 P surface with an improvement in the surface topography. Moreover, the possibilities of interactions such as hydrogen bonding among the oxygen functional groups in CoO/rGO, with phosphorus in Ni 2 P, lead to an intimate contact among them for the fast electronic movement for proton reduction. Consequently, the CoO/rGO-Ni 2 P composite coating displays a benchmark performance for solar-driven hydrogen generation and produces 4.98 mmol/g hydrogen for 1 h irradiation after a successful compositional tuning. The long-lasting activity and excellent stability of the composite coating, even after 15 cycles, are attributed to the additional role of Ni 2 P as a catalyst support bed for CoO/rGO which can impart stability to the entire catalyst system.