Enhanced Photocatalytic H2O2 Production over Carbon Nitride by Doping and Defect Engineering

Photocatalytic production of H 2 O 2 from the reduction of O 2 by semiconductor photocatalysts (e.g., graphitic carbon nitride, C 3 N 4 ) has been regarded as an alternative for small-scale decentralized H 2 O 2 production. However, the efficiency of pristine C 3 N 4 photocatalysts is still limited by the narrow light absorption range and rapid charge recombination. Here, we presented a facile approach to simultaneously enhance the light absorption and promote the charge separation by introducing alkali metal dopants and N vacancies on C 3 N 4 . The introduction of alkali metal dopants and N vacancies successfully broadened the light absorption range, reduced the band gap from 2.85 to 2.63 eV, and greatly inhibited the charge recombination. The synergistic effect of doping and defect resulted in the improvement of photocatalytic performance with a H 2 O 2 production rate of 10.2 mmol/h/g, which is 89.5 times that of pristine C 3 N 4 . Thus, this work not only gives insights into the synergistic effect of doping and defect for simultaneously manipulating the light absorption and charge separation processes but also inspires further work to develop more efficient photocatalysts for H 2 O 2 production.