MnOx-decorated 3D porous C3N4 with internal donor–acceptor motifs for efficient photocatalytic hydrogen production

Carbon nitride is an intriguing visible-light photocatalyst for H 2 production but suffers from low surface area and fast charge recombination. Here, we report a simple yet efficient approach to fine tune the porous structure, modify the electronic structure and carrier behaviors of C 3 N 4 through in-situ growth of MnO x by NaCl template-assisted strategy. This NaCl template method simultaneously constructs 3D porous structure for high surface area, induces Na coordination with N atoms and accompanying cyano group to form an internal donor-acceptor system for efficient charge transfer and separation. Along with the MnO x growth, the band gap of C 3 N 4 is narrowed for stronger visible light absorption and the conduction band level is negatively shifted for stronger reduction capability. Thus, the resulted C 3 N 4 (MSCN) shows much improved activity of about 18 times higher than bulk C 3 N 4 in photocatalytic hydrogen evolution reaction under visible light irradiation.