Enhanced solar-light driven H2O2 2 O 2 production with g-C3N4 3 N 4 nanosheets by defect engineering

Defective g-C3N4 3 N 4 nanosheets were prepared using hydrothermal treatment followed by heating with NaBH4. 4 . The structure, optical property and charge carrier transfer of samples were systematically studied. The nanosheet structure with large specific surface area could provide more active sites for photocatalytic reaction. Meanwhile, the introduction of nitrogen vacancies not only reduced the bandgap and extended the light absorption edge, but also accelerated the charge carrier separation and transfer. Therefore, the defect-rich g-C3N4 3 N 4 nanosheets exhibited much higher H2O2 2 O 2 production capacity (329.6 mu mol h-1g-1) g-1 ) than bulk g-C3N4 3 N 4 (73.1 mu mol h-1g-1) g-1 ) and the solar-to-chemical energy conversion (SCC) efficiency reached 0.38%. The superoxide radical (center dot O2- center dot O 2- ) was determined to be the key species for hydrogen peroxide production via two-electron reduction of O2. 2 . This work demonstrates a promising synthetic strategy for efficient H2O2 2 O 2 evolution with solar energy based on defective gC3N4. 3 N 4 .