Isotype junctioned nanotubes and nanosheets of g-C3N4 for enhanced visible-light driven photocatalytic H2O2 production

Graphitic carbon nitride (g-C3N4) has emerged as a rising star for photocatalytic H2O2 production, but is still challenging to achieve high activity because of insufficient visible-light response, rapid charge recombination and low-specific surface area. Herein, we report the construction of g-C3N4/g-C3N4 isotype junction composed of nanotubes and nanosheets by thermal polymerization treatment of the mixture of urea and thiourea. It demonstrated significantly enhanced visible-light-driven photocatalytic activity of H2O2 production (785 μmol g−1 h−1) over its counterpart pure C3N4 moieties derived from urea or thiourea individually. The excellent photocatalytic performance can be explained by the synergistic effects of electronic band alignments and nanostructures. Type-II band alignment, nitrogen vacancies and intimate interface contact were developed between the nanotubes and nanosheets, which promoted visible-light response, separation of photogenerated electron–hole pairs, and charge and mass transport. This work presents a potent example of designing isotype junctions with special nanostructures for enhancing H2O2 production performance of g-C3N4-based photocatalysts.