The biopolymer-assisted synthesis of assembled g-C3N4 open frameworks with electron delocalization channels for prompt H2 production

Abstract

Three-dimensional (3D) photocatalysts can overcome the serious aggregation exhibited by two-dimensional (2D) nanosheets caused by unavoidable van der Waals forces. However, the water splitting efficiency needs further improvement, which can be achieved by boosting the exciton dissociation and charge transfer. Herein, a gelatin-confined strategy is developed to construct 3D tube-assembled g-C₃N₄ open frameworks. The gelatin plays multiple roles in the thermal polymerization. It not only engineers the grain growth of g-C₃N₄, but also supplies in situ external C and O sources. Experimental and density functional theory (DFT) calculation results indicate that the self-integration effects of the unique 3D architecture and bridging electron delocalization channels lead to prompt exciton production and dissociation, and subsequent carrier transfer. Consequently, the g-C₃N₄ open framework achieves a hydrogen evolution rate of 99.4 μmol h⁻¹ and an apparent quantum efficiency of 7.43% at 450 nm, significantly superior to previously reported C and (or) O-doped 2D g-C₃N₄ and other 3D g-C₃N₄ materials. These findings provide promising guidance for designing efficient 3D architectures to drive photocatalysis and support the broader application of cost-effective biopolymers.