Regulation on polymerization degree and surface feature in graphitic carbon nitride towards efficient photocatalytic H2 evolution under visible-light irradiation

A kind of graphitic carbon nitride (TSC-550) with high polymerization degree and improved surface property was prepared by a new precursor of thiosemicarbazide. The sulfur motif and high nitrogen content in thiosemicarbazide promoted the polymerization of thiosemicarbazide to form graphitic car-bon nitride framework with high degree of polymerization, which significantly influenced the electronic structure and surface chemical properties. TSC-550 possessed a narrow bandgap of 2.19 eV that facili-tated the utilization of visible light, and possessed a less positive charge, acidic surface that resulted in enhanced hydrogen adsorption ability in water solution, which promoted the H-2 evolution kinetics. In addition, the extended pi-conjugated electronic system promoted the separation and migration of photo-generated charge carries in plane of TSC-550 framework, as well as the increasing interlayer C-N in-teractions in TSC-550 created conductive paths across the layers to tunnel interlayers for rapid electron transportation. As a result, TSC-550 nanosheets showed excellent photocatalytic H-2 production activity, the AQY achieved 36.4% at 425 nm. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.