Controlled synthesis of hollow carbon ring incorporated g-C3N4 tubes for boosting photocatalytic H2O2 production

H2O2 production through solar-driven photocatalytic route has received increasing attention. Herein, a carbon ring incorporated hollow g-C3N4 tubes (CHCN) was successfully fabricated via a novel supramolecular selfassembly strategy, co-inducing by hydrogen bond and covalent bond. The optimum H2O2 yield over the CHCN-0.02 reached up to 1.58 mmol L-1 h-1 (AQE= 28.10%, 420 nm), which was 5.4 times significantly higher than that of bulk g-C3N4 (0.29 mmol L-1 h-1) under visible light irradiation. Experimental and density functional theory (DFT) calculations revealed that the CHCNs not only expedited the charge carrier transfer/separation but also favored molecular oxygen adsorption and regulated bandgap structure under the in-plane electronic field induced by continuous & pi;-conjugated Cring, which boosted the ORR efficiency for photocatalytic H2O2 synthesis. The optimized CHCN catalyst demonstrated adequate hybrid ORR routes, consisting of a dominated selective one-step two-electron ORR pathway and highly efficient two-step single-electron ORR for H2O2 production. Therefore, this work not only provides a new strategy for an efficient H2O2 formation using a g-C3N4-based photocatalyst but also explores the functionary mechanism of the ORR process and enlightens the way to highly efficient H2O2 generation.

Automated summary

Solar-driven photocatalytic route for H2O2 production has gained attention. Carbon ring incorporated hollow g-C3N4 tubes (CHCN) with significantly higher H2O2 yield than bulk g-C3N4 were successfully fabricated. The optimized CHCN catalyst demonstrated efficient ORR routes for H2O2 production. This work provides a new strategy for efficient H2O2 formation and explores the mechanism of the ORR process for highly efficient H2O2 generation.