Significantly influenced photocatalytic performance for H2O2 generation over ultrathin g-C3N4 through regulating the migration orientation of photogenerated charge carriers

H2O2 has been widely applied in the fields of chemical synthesis, medical sterilization, pollutant removal, etc., due to its strong oxidizing property and the avoidable secondary pollution. Despite of the enhanced performance for H2O2 generation over g-C3N4 semiconductors through promoting the separation of photo-generated charge carriers, the effect of migration orientation of charge carriers is still ambiguous. For this emotion, surface modification of g-C3N4 was employed to adjust the migration orientation of charge carriers, in order to investigate systematically its effect on the performance of H2O2 generation. It was found that ultrathin g-C3N4 (UCN) modified by boron nitride (BN), as an effective hole-attract agent, demonstrated a significantly enhanced performance. Particularly, for the optimum UCN/BN-40% catalyst, 4.0-fold higher yield of H2O2 was obtained in comparison with the pristine UCN. As comparison, UCN modified by carbon dust demonstrated a completely opposite tendency. The remarkably improved performance over UCN/BN was ascribed to the fact that more photo-generated electrons were remained inside of triazine structure of g-C3N4, leading to the formation of larger amount of 1,4-endoxide. It is anticipated that our work could provide new insights for the design of photocatalyst with significantly improved performance for H2O2 generation.