Nitrogen-defective g-C3N4 with enhanced photocatalytic performance fabrication by destructing C=N-C bond via H2O2

The g-C3N4 nanosheets with N-defects were fabricated by a sample oxidative reaction via H2O2, which can generate hydroxyl radical (center dot OH) to destruct the bonds of g-C3N4. The existence of center dot OH was confirmed by PL (photoluminescence spectroscopy) and HPIC (high-pressure ion chromatography). The N-defects were confirmed by the concentration of nitrate in solution increasing from 1.04 to 4.65 mg/L. Further, the source of N-defects was speculated as the destruction of C=N-C due to its lower bond-energy and decreasing ratio of C=N-C (CASTEP, XPS). As a result, the obtained N-defective g-C3N4 improved the photocatalytic degradation efficiency to Methylene blue (MB) from 53.1% (g-C3N4) to 100.0% under visible light. This result was ascribed by the N-defect narrowed the bandgap from 2.71 to 2.67 eV, accelerated the separation and transfer of photo-generated carriers. This work provides a new strategy to construct defects in a catalyst improving photocatalytic performance.

Automated summary

N-defective g-C3N4 nanosheets were fabricated through a sample oxidative reaction using H2O2, improving the photocatalytic degradation efficiency of Methylene blue (MB). The existence of hydroxyl radicals (center dot OH) and N-defects were confirmed by PL and HPIC, respectively, with an increase in nitrate concentration in solution. The N-defects were speculated to originate from the destruction of C=N-C bonds, leading to a narrowed bandgap and enhanced separation and transfer of photo-generated carriers.