Morphology distortion endowing highly asymmetric skeleton in carbon nitride nanosheets for boosted photocatalytic overall water splitting

Symmetrical planar unit cells and periodic layered structures of polymeric photocatalysts are the roots of poor light absorption and severe carrier recombination in photochemical process, which in turn diminish redox capabilities during photocatalytic overall water splitting. In this study, we synthesized porous and curled carbon nitride nanosheets (U-A400) featuring imperfect molecular structures through polycondensation of an asymmetric precursor molecule and a soft template. The twisted framework in U-A400 promoted strong n -> pi* electron transitions, generating a considerable built-in electrical field and prolonging the average fluorescence lifetime. Additionally, the structural distortion increased the number of surface acid-base active sites. Consequently, these adjustments in the micro- and topological structures rendered U-A400 highly effective for photocatalytic overall water splitting, achieving H-2 and O-2 average evolution rates of 65.93 and 38.53 mu mol g(-1)h(-1), respectively, over 4 h of visible light (lambda > 420 nm) irradiation, 38 times higher than those of graphitized carbon nitride. This work presents valuable insights into the development of advanced polymeric photocatalysts, efficiently harnessing sunlight for overall water splitting, thereby contributing to sustainable energy conversion and clean fuel production.