NiTiO3/Co3S4 nanoflowers: Solar-driven Z-scheme photocatalysts for efficient water purification

The growing issue of environmental pollution, particularly water contamination by the spread of bacteria and organic dyes, eagerly demands to be resolved. Given its advantages of being efficient, convenient, and eco-friendly, photocatalysis stands out as a promising strategy for water purification. To harness solar energy effectively, Co 3 S 4 nanodots with a narrow band gap were integrated onto the surface of NiTiO 3 nanoflowers to construct heterostructure (NC-x). Detailed characterization revealed that the charge transfer mechanism belonged to a novel Z-scheme, which not only facilitated efficient electron-hole separation into different components but also maintained a high redox potential, leading to the generation of plenty of reactive oxygen species (ROS: . O 2 - and . OH). These ROS were instrumental in damaging bacteria and the degradation of organic dyes. Furthermore, the NC-x nanocomposite exhibited excellent photothermal property and the local hyperthermia further enhanced the photocatalytic reaction. Optimized for composition, NC-2 shows the effective inactivation to E. coli, achieving a lethality rate of 99.50±0.22 % under simulated sunlight irradiation. It has also been successfully applied to treat complex lake water samples, demonstrating significant antibacterial (99.82±1.28 %) and methylene blue (90.60±1.78 %) degradation efficiency, simultaneously. With the novel biocompatibility and decontamination capabilities, NC-2 holds substantial potential for water purification applications.