3D/2D coral-like C3N5/Ti3C2 MXene Schottky heterojunction for enhanced photocatalytic H2 evolution

The C3N5 is broadly applied in photocatalytic conversion owing to its narrow band gap and excellent visible light absorption. Nevertheless, realizing efficient separation of photogenerated charge carriers on C3N5 is still challenging. Herein, a 3D/2D C3N5/Ti3C2 Schottky heterojunction (PCN/TC) was constructed by combining 3D coral-like C3N5 with Ti3C2 MXene nanosheets through direct electrostatic self-assembly technique. Benefiting from the peculiar structure of C3N5 and the establishment of C3N5/Ti3C2 Schottky heterojunction, the H2 evolution yield of the optimized PCN/TC (2581.23 μmol‧g−1‧h−1) is 8.3 and 2.6 times higher than that of bulk C3N5 and coral-like C3N5, respectively. The mechanism for improving photocatalytic performance is proposed by physical and chemical characterization analysis. Specifically, structural modification of C3N5 resulted in an increase in specific surface area along with a reduction in the diffusion distance of photoexcited electrons. Besides, Ti3C2 possesses enriched active metal sites, further augmenting photocatalytic H2 production performance. The tight interfacial contact of PCN/TC effectively promotes the photoexcited electrons migration from C3N5 to Ti3C2. Moreover, the formed Schottky barrier constitutes a unidirectional pathway for electron transfer, realizing efficient spatial separation of photogenerated carriers. The research offers a novel approach to producing C3N5-based efficient photocatalysts for photoconversion applications.