Tailoring boron doped intramolecular donor-acceptor integrated carbon nitride skeleton with propelling photocatalytic activity and mechanism insight

Graphite phase carbon nitride (CN) is an authenticated promising photocatalyst for addressing the global environmental issue and energy crisis, while the ready recombination of carriers, low exposure of active sites and insufficient visible-light harvesting remarkably hamper its photocatalytic activity. To overcome these drawbacks, a boron doped intramolecular donor-acceptor (D-A) integrated CN with propelling photocatalytic performance was fabricated via facile thermal-melting followed thermal induce copolymerization of urea with m-aminophenylboronic acid. The optimized CN25 photocatalyst exhibits porous nano lamellate morphology, large specific surface area, superhydrophilicity, enlarged visible-light utilization and effectively suppressed carrier recombination. Under visible-light irradiation, the CN25 can generate H2 with the rate of 1914 mu mol g- 1h- 1 (5.9 times of pristine CN), which also significantly higher than that of other CN with m-aminophenol or aniline as dopant. Marvelously, the CN25 (10 mg) can degrade 81.3% high concentration tetracycline (40 mg L-1) within 100 min, which is 6.75 times of pristine CN. The capture experiments and ESR analysis prove that high 1O2 and center dot O2- yield contribute to the photodegradation process. The LC-MS and on-line FT-IR revealed degradation intermediates & routes and real-time monitor the changes of functional groups in the photodegradation process. The PL, timeresolved PL, EIS, PCR, UV-vis DRS and band gap analysis confirm that the CN25 exhibits more efficient exciton dissociation and carrier migration dynamics in contrast to pristine CN. Finally, the electron density of the HOMO/LUMO, molecular dipole, electrostatic potential and density of states further confirm the formation of DA structure and explicate the potential boost mechanism of photocatalytic activity. This work opens a new route for simply, environmental-friendly and cost-effectively propelling activity of CN photocatalysts for environmental remediation and clean energy production.

Automated summary

Boron-doped carbon nitride materials can greatly enhance the photocatalytic activity, with porous nano lamellate morphology and large specific surface area, enabling efficient degradation of pollutants and hydrogen generation. Capture experiments confirmed the generation of high 1O2 and •O2- species, making the photodegradation process more effective. The experimental results also demonstrated improved kinetics of exciton dissociation and carrier migration for the doped materials. This work provides a new approach to enhance the activity of carbon nitride photocatalysts.