0D/2D heterojunctions, especially quantum dots (QDs)/nanosheets (NSs) have attracted significant attention for use of photoexcited electrons/holes due to their high charge mobility. Herein, unprecedent heterojunctions of vanadate (AgVO₃, BiVO₄, InVO₄ and CuV₂O₆) QDs/graphitic carbon nitride (g‐C₃N₄) NSs exhibiting multiple unique advances beyond traditional 0D/2D composites have been developed. The photoactive contribution, up‐conversion absorption, and nitrogen coordinating sites of g‐C₃N₄ NSs, highly dispersed vanadate nanocrystals, as well as the strong coupling and band alignment between them lead to superior visible‐light‐driven photoelectrochemical (PEC) and photocatalytic performance, competing with the best reported photocatalysts. This work is expected to provide a new concept to construct multifunctional 0D/2D nanocomposites for a large variety of opto‐electronic applications, not limited in photocatalysis.

Hydrogen from photocatalytic water splitting is a sustainable and renewable source of clean energy.