Cyano-Rich Porous Carbon Nitride Nanosheets for Enhanced Photocatalytic H2o2 Production

Abstract

The gas template method is used to introduce the cyano (-C≡N) group and porous thin-layer structure into g-C3N4 simultaneously. The resulting material exhibits a synergistic effect between the -C≡N group and porous thin-layer structure, which broadens the optical absorption range of g-C3N4 and enhances electron transfer and transformation. The rotating ring-disk electrode (RRDE) experiments demonstrate that cyano-rich porous ultrathin carbon nitride significantly improves the selectivity of 2e- oxygen reduction reaction (ORR), with the selectivity of 93% compared to the 66% of the original carbon nitride at a potential of 0.3V versus RHE. Additionally, the H2O2 yield for the modified carbon nitride is twice than that of the original carbon nitride material (99.11 μM vs 49.79 μM). The mechanism for photocatalytic H2O2 production involves a two-step one-electron reaction. The modified catalyst is recyclable and can be used for an extended period of time. Overall, this study provides a viable method for modifying g-C3N4 to improve its photocatalytic activity and selectivity towards the 2e- ORR.

Keywords: gas template method, porous thin-layer structure, carbon nitride, photocatalytic H2O2 production