Facile synthesis of peptides anchored g-C3N4 nanosheets for efficient photocatalytic hydrogen generation

Abstract

This work demonstrated the synthesis of peptides decorated porous g-C3N4 hybrids (R-CN) for the enhanced photocatalytic H2 production, where the 14-mer peptides were effectively deposited on g-C3N4 nanosheets by electrostatic interaction. The prepared R-CN hybrid composite shows the enhanced visible light absorption due to the modulation of electronic structures of g-C3N4 by the interaction between peptides and g-C3N4. Therefore, the R-CN hybrid composite demonstrated the excellent photocatalytic H2 production with yield of 2018 μmol·g−1·h−1 under the visible light irradiation, which is 14-time higher than that of pristine g-C3N4. The theoretical study shows that the strained heptazine planes in the g-C3N4 structure is formed in the R-CN hybrid composites by the electrostatic interaction between the positively charged amine group of peptides and the negatively charged edge N atom of g-C3N4. Thus, the electron redistribution and delocalization in the R-CN composite lead the band gap reduction, build-in electrical field and electronic modulation. Therefore, the R-CN composites shows the enhanced charge separation and the optimized free energy of reaction intermediates for the excellent photocatalytic activities. These results are confirmed from the experimental measurements and the MD and DFT computations study. This work provides an effective strategy to design biomaterial-based metal-free photocatalysts for H2 production.