Optimizing photocatalytic H2O2 production through morphology-controlled supramolecular self-assembly of porous carbon nitride nanotubes via C6N6 rings

The solar-driven photocatalytic H2O2 generation is an eco-friendly, energy-saving, and promising technology. Herein, porous g-C3N4 nanotube (TCN) with controllable morphology was successfully synthesized, and it was first reported that the formation of C6N6 ring promoted supramolecular self-assembly. The H2O2 yield of TCN corresponded well (R2=0.984) with the contents of C6N6 ring in TCN, which could be well modulated by the ratio of urea and melamine, and the optimal performance was achieved at a ratio of 10:1 (TCN10). The H2O2 was generated on the surface of TCN10 through continuous two-step single-electron oxygen reduction reaction, with its formation kinetic constant and yield 7.32 and 7.38 times higher than those of pristine g-C3N4. The C6N6 ring enriched e- in O2 adsorption area, promoting the transfer of e- from TCN10 to O2, thereby reducing the energy barrier for generating H2O2. This study provided a promising strategy for H2O2 generation with controllable morphology and C6N6 ring.