Boosting photocatalytic antibiotic degradation with simultaneous H2O2 production of g-C3N4 by building dual-dragging force for efficient charge separation

Abstract

Graphitic carbon nitride (g-C3N4) is a promising candidate for photocatalytic antibiotic degradation with simultaneous H2O2 production. However, g-C3N4 suffers from a high charge recombination and insufficient visible-light absorption. Herein, the benzene-ring and cyano groups were successfully grafted onto the surface of g-C3N4 (BCN-ND) by a simple coupling route involving copolymerization and secondary calcination, which provided a dual-dragging force was generated for the directional separation of photogenerated electrons and holes. The benzene-ring establishes a mid-state slightly above the valence band, which results in a dragging force for holes and extends the response of g-C3N4 to visible light. Moreover, the cyano group exhibits a powerful electron-withdrawing capacity, acting as an electron-dragging force and narrowing the intrinsic bandgap. Therefore, BCN-ND exhibits remarkable photocatalytic activity with a sulfamethoxazole degradation percentage of 99.5 % and simultaneous H2O2 production of 62 μmol/L after 80 min of visible light irradiation. This work provides new perspectives for enhancing photocatalytic activity by constructing of a dual-dragging center for oppositely directional charge separation.