The synthesis of 3D organic-inorganic hybrid heterojunctions of g-C 3 N 4 nanoneedles@Ti 3 C 2 MXene with superior photocatalytic H 2 evolution.

3D organic-inorganic hybrid heterojunctions of 1D carbon nitride (g-C 3 N 4 ) nanoneedles anchoring on 2D Ti 3 C 2 MXene nanosheets have been constructed via a green molten salt treatment. The Ti 3 C 2 MXene nanosheets and molten salt treatment guide the formation of ordered nanoneedle-like g-C 3 N 4 . Both the formed heterojunctions and the nanoneedle-like structures contribute charge separation and transfer for superior photocatalytic H 2 evolution.