Rational design and fabrication of effective multi-component cocatalyst for high performance photocatalytic hydrogen production via water-splitting have been investigated. Herein, polyaniline-derived N-doped carbon encapsulated copper/copper phosphide nanoparticles (Cu/Cu_xP@NC) was facilely prepared by a single-step phosphorization-pyrolysis route. Homologous Cu/Cu_xP heterostructure with a diameter ∼ 20 nm was successfully wrapped with N-doped carbon layers. The resultant Cu/Cu_xP@NC is utilized as a cocatalyst of host photocatalysts like TiO₂ and g-C₃N₄ for H₂ generation. The optimal Cu/Cu_xP@NC/TiO₂ composites exhibited a hydrogen evolution rate (HER) of 12.45 mmol.h⁻¹ g⁻¹ which is 145-fold higher than TiO₂ alone. Interestingly, the Cu/Cu_xP@NC composite also improved the activity of g-C₃N₄ to produce 285 µmol.h⁻¹ g⁻¹ of H₂ under visible light where no H₂ was evolved over pure g-C₃N_4. The photocatalytic performance of the presented Cu/Cu_xP@NC/TiO₂ was superior than carbon-free Cu/Cu_xP/TiO₂ nanocomposite. Such improved activity is attributed to the N-doped carbon layer that plays a pivotal role in suppressing the recombination of the photogenerated electron-hole pairs. Thus, Cu/Cu_xP@NC cocatalyst composite can efficiently capture the photoexcited electrons from the conduction band of TiO₂ or g-C₃N₄, accelerating the charge separation process. This study provides a low-cost and competitive cocatalyst to substitute noble metals in photocatalytic reactions.