2D heterojunction of C, N, S co-doped TiO 2 /g-C 3 N 4 nanosheet with high-speed charge transport toward highly efficient photocatalytic activity

Z-type 2D/2D C, N, S co-doped TiO 2 /g-C 3 N 4 (DTCN) photocatalysts possessing high catalytic activity were prepared via a simple ultrasonic recombination method. The catalysts’ microscopic morphology, crystal structure, chemical composition, and optical properties were investigated with scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and ultraviolet–visible tests. The photocatalytic activity was also assessed via the degradation of the organic pollutant RhB. The results showed that DTCN could achieve 85.3% degradation of the target pollutant within 60 min, which was 2.47 times (34.5%) and 1.76 times (48.5%) more than TiO 2 and g-C 3 N 4 . The first-order kinetic constants of DTCN reached 0.02838, which was 4.11 and 2.66 times that of TiO 2 and g-C 3 N 4 . Nonmetallic C, N, S (CNS) co-doping effectively improved sunlight utilization of TiO 2 nanosheets through the generation of impurity bands in the forbidden band area. The Z-type heterojunction formed via the coupling of g-C 3 N 4 and CNS–TiO 2 promoted the separation of photoinduced carriers and improved the charge transfer efficiency, boosting the TiO 2 photocatalytic performance. Furthermore, the 2D–2D heterojunction provided a high-speed transport channel for charges. Graphical Abstract Z-type 2D–2D DTCN nanosheet heterojunctions were successfully fabricated. Nonmetallic CNS co-doped effectively improved sunlight utilization of TiO 2 nanosheets through the generating of impurity bands in the forbidden band area. Furthermore, the Z-type heterojunction formed via the coupling of g-C 3 N 4 and CNS–TiO 2 promoted the photoinduced carrier separation and improved the charge transfer efficiency, so boosting the TiO 2 photocatalytic performance.