Heterostructure formation is an effective method used for designing photocatalysts that solve problems caused by photoexcited charge recombination phenomena associated with the photocatalytic water redox reaction. This work reports a new Co-metal-incorporated ternary heterostructured photocatalyst, CdS/CoO x /Co-metal, which enhanced charge separation to increase photocatalytic H2 evolution 30.5-fold in comparison to pure CdS under visible light. This work demonstrates for the first time the effect of the Co metal on photocatalytic H2 evolution using the CdS/CoO x /Co-metal ternary heterostructure. In the ternary heterostructure, Co metal and CoO x act as photogenerated electron- and hole-capturing cocatalysts, respectively. Results from photoelectrochemical studies along with photocatalytic H2 evolution data proved the enhancement of charge transfer and separation in the CdS/CoO x /Co-metal heterostructure due to the addition of Co metal and CoO x . Hence, the synergistic charge separation improvement achieved by the combination of CoO x and the Co metal with CdS produced a photocatalytic H2 evolution rate of 9.54 μmol/h, which is the highest reported H2 evolution rate for a CdS-based system under l sun solar irradiance (>420 nm) to the best of our knowledge.