Preparation of donor-π-acceptor type graphitic carbon nitride photocatalytic systems via molecular level regulation for high-efficient H2O2 production

Abstract

Donor-π-Acceptor (D-π-A) conjugated polymers represent an emerging class of materials featuring alternating electron donor (D), π-bridge (π), and electron acceptor (A) units, which exhibit significant potential in enhancing visible-light absorption and optimizing charge separation and redistribution. To overcome the limitations of graphitic carbon nitride (g-C₃N₄) while capitalizing on the structural merits of D-π-A systems, a series of 4-aromatic amine derivatives modified g-C₃N₄ photocatalysts was designed and synthesized through precise molecular level regulation with tailored local electron delocalization. This strategy allows for a systematic investigation of the relationship between electron delocalization extent and photocatalytic H₂O₂ production. Furthermore, the electron-withdrawing induction effect for regulating electron delocalization results in a substantial enhancement of photoinduced electron transfer to surface reactive sites. The as-synthesized optimum photocatalyst exhibits a remarkable H₂O₂ production performance, which is 30.44 times higher than that of the pristine g-C₃N₄. The mechanism study reveals that the photocatalytic H₂O₂ production in D-π-A-type g-C₃N₄ proceeds primarily via a two-electron oxygen reduction reaction (ORR).