On the basis of a simple ion exchange method, a MoS₂/g-C₃N₄/graphene oxide (GO) ternary nanojunction was constructed as an efficient photocatalyst for hydrogen evolution using solar energy. The confinement effect in MoS₂ and g-C₃N₄ quantum dots enhances their water-splitting redox activities. The designed heterostructure featured a band alignment that facilitates the collection of electrons in MoS₂ and holes in g-C₃N₄, effectively suppressing the recombination of photogenerated charge carriers. Furthermore, the GO with high specific surface area serves as an excellent conductive substrate to transport holes speedily. This study thus provides a novel and facile route of establishing efficient composite photocatalyst with multinary components for energy conversion.