Construction of tubular g-C3N4/TiO2 S-scheme photocatalyst for high-efficiency degradation of organic pollutants under visible light

Graphitic carbon nitride (g-C3N4) is a promising photocatalyst with lots of merits, such as visible light driven (200–1000 nm), cost-effective and high stability. However, the single g-C3N4 photocatalyst is limited in its performance due to the high complexation rate of photogenerated electrons and holes and the confined specific surface area. Herein, a S-scheme heterojunction catalyst involving tubular g-C3N4 (TCN) and TiO2 is designed and constructed via precursor reforming strategy with subsequent hydrothermal calcination process. The tubular structure offers more active centers, conducive to light absorption and contact with pollutants, while the heterojunction facilitates the transfer and separation of electrons and holes. Thus, the TCN/TiO2 catalyst exhibits excellent photocatalytic activity with degradation efficiencies for methylene blue (MB) and tetracycline (TC) reaching 96.6 % and 100 %, respectively, as well as high degradation efficiency for other dyes (Congo red and Eosin y). Besides, TCN/TiO2 catalyst demonstrates outstanding stability and potential for practical application. An innovative S-scheme heterojunction system has shown remarkable potential for improving the separation and transferring electron-hole pairs, as well as delivering stronger redox capability. This work provides a promising strategy for the preparation of g-C3N4/TiO2 catalyst for the effective treatment of contaminated water.