Regulation of oxygen reduction pathway on carbon nitride for enhanced H2O2 photosynthesis

Photocatalytic oxygen reduction reaction (ORR) to produce H 2 O 2 on graphitic carbon nitride (CN) has been regarded as a green and sustainable route by using endless solar energy. However, this process is limited by side-reactions of single electron transfer process, thus decreasing the overall efficiency. Herein, we have proposed an effective method to optimize H 2 O 2 photosynthesis by modulation of oxygen reduction pathway. That is modification of CN by introducing cyano groups and N defect in the presence of NaBH 4 . The H 2 O 2 production rate was 570 μmol/g/h by the optimal photocatalyst of BCN, showing 11-fold enhanced efficiency. Mechanism analysis proved that the convert of the single electron oxygen reduction in pristine CN into two-electron pathway in B x CN occurred, which contributed to improved ORR efficiency and accelerated conversion of O 2 •− on H 2 O 2 photosynthesis. This work revealed an effective method for optimizing H 2 O 2 photosynthesis by regulating oxygen reduction reaction pathway. In this work, throughout the regulation of oxygen reduction reaction pathway, we demonstrate that carbon nitride modified by NaBH 4 can act as efficient catalyst for H 2 O 2 photosynthesis without any sacrificial agents. • C 3 N 4 is modified by pyrolysis treatment in the presence of NaBH 4 . • BCN exhibits excellent H 2 O 2 photosynthesis under visible light and pure water. • The ORR pathway is regulated to convert from single electron to two-electron transfer.