K-doped g-C3N4 decorated with Ti3C2 for efficient photocatalytic H2O2 production

Abstract

Hydrogen peroxide (H₂O₂) is an important chemical widely used in the chemical industry. However, the current technical methods of producing H₂O₂ are limited by high cost, excessive energy consumption and environmental impact. Here, we construct Ti₃C₂ to modify K-doped g-C₃N₄ heterojunctions for the production of H₂O₂. Through the pretreatment of K-doped g-C₃N₄ and the electrostatic self-assembly method, Ti₃C₂ is closely bonded to effectively adjust the band position, resulting in a good synergistic effect and an excellent photogenerated electron transfer ability. The construction of this structure has improved the yield of H₂O₂ and the production of H₂O₂ under visible light illumination reached as high as 3401 μmol L⁻¹, which is much higher than that of g-C₃N₄. In addition, the photocatalytic mechanism shows that the two-step single-electron reduction of O₂ is the main reaction step of H₂O₂ production. The improvement of photocatalytic performance can be attributed to the doping of K and the construction of the heterojunction, which not only expands the absorption range of visible light, but also inhibits the recombination of photogenerated electron–hole pairs and accelerates carrier separation. At the same time, the catalyst has good stability and can be recycled. This work provides a deep understanding of the modification of g-C₃N₄ and a new strategy for the development of high-efficiency H₂O₂-producing photocatalysts.