2D/2D Interface Engineering Promotes Charge Separation of Mo 2 C/g-C 3 N 4 Nanojunction Photocatalysts for Efficient Photocatalytic Hydrogen Evolution.

The focus of designing and synthesizing composite catalysts with high photocatalytic efficiency is the regulation of nanostructures and optimization of heterojunctions. By increasing the contact area between the catalysts, additional reaction sites can be established and charge carriers can be transferred and reacted faster. Here, two-dimensional (2D) Mo 2 C is prepared via a novel approach by carbonizing precursors intercalated by low-boiling solvents, and a composite catalyst Mo 2 C/graphitic carbon nitride (g-C 3 N 4 ) with 2D to 2D structure optimization was synthesized through the self-assembly of 2D Mo 2 C and 2D g-C 3 N 4 . The hydrogen production rate of the photocatalyst at the optimal ratio is 675.27 μmol g -1 h -1 , which further exceeds 2D g-C 3 N 4 . It is 5.1 times that of the 7 wt % B/2D Mo 2 C/g-C 3 N 4 photocatalyst and also 3.5 times that of 0.5 wt % Pt/g-C 3 N 4 . The enhanced photocatalytic activity is attributed to the fact that Mo 2 C as a cocatalyst can rapidly transfer the photogenerated electrons of g-C 3 N 4 to the surface of Mo 2 C, and the 2D to 2D structure can provide abundant reaction sites for photogenerated electrons to prevent their recombination with holes. This study provides new ideas and techniques for the development of 2D platinum-like cocatalysts and the optimization of nanojunctions.