Facile synthesis of g-C3N4 nanosheets homojunction for enhanced photocatalytic oxygen reduction reaction

Abstract

A g-C₃N₄ homojunction was fabricated by thermal etching a mixture of two bulk phases of g-C₃N₄ derived from various precursors in a 1:1 mass ratio. A larger specific surface area of 144.2 m² g⁻¹ was obtained and offered more reaction active sites for photocatalytic production of hydrogen peroxide (H₂O₂). Meanwhile, the built-in electric field formed by the homojunction structure facilitated the separation of charge carriers and prolonged lifetime, and the charge transfer pathway of g-C₃N₄ homojunction aligned with a type-Ⅱ heterojunction mode. Within 60 min, the H₂O₂ yield and tetracycline degradation efficiency of g-C₃N₄ homojunction reached 414.6 μM and 82.1%, respectively, which were significantly higher than those of the two bulk phases of g-C₃N₄. In addition, the photocatalytic reaction route of H₂O₂ production was confirmed as a continuous single-electron oxygen reduction reaction process. This study introduces a new way to practically apply g-C₃N₄-based materials in H₂O₂ synthesis