Synergy between sulfur vacancy and Schottky junction into CoB/ZnIn2S4–S photocatalysts: Oriented charge flow and regulated carriers transfer dynamics to activate reactive oxygen species generation for efficient photocatalytic disinfection

• Published in: Journal of cleaner production Vol. 387; p. 135742
• Main Authors: Liu, Hui-Yun, Niu, Cheng-Gang, Huang, Da-Wei, Guo, Hai, Li, Meng-Ke, Yang, Ya-Ya, Tang, Ning, Li, Lu, Zhang, Lei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.02.2023
• Subjects: DFT calculation; ROS formation; Schottky heterojunction; Sulfur vacancy; Water disinfection; Schottky heterojunction; DFT calculation; Sulfur vacancy; Water disinfection; ROS formation
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2022.135742

To maximize the phocatalytic activity, semiconductor-based catalysts need to be properly modified in various methods. Here, a feasible synergistic strategy is proposed for enhancing the photocatalytic property. We firstly combine 2D ZnInS4–S nanosheets with amorphous CoB nanoparticles to obtain hybrid catalysts with Schottky junction and S vacancy engineering, and indicate that the CoB/ZnInS4–S with the synergistic effect owns efficiently improved photocatalytic antibacterial performance. Based on systematic characterization technologies and theoretical calculations, it is concluded that the wonderful photocatalytic activity of CoB/ZnIn2S4–S results from enhanced light-harvesting ability, accelerated charge-carriers separation, high specific surface area and more active sites. Moreover, the upward band bending resulted from the difference in work function between two components causes the directional electrons flow from ZnIn2S4–S to CoB, inhibiting the electron backflow and stimulating more reactive oxygen species (ROS) formation. Meanwhile, S vacancy can capture electrons to boost charge-carriers separation. As a result, the optimal 2CoB/ZnIn2S4–S composite can thoroughly inactivate 6.18-log of E. coli under 100 min of visible light illumination. Furthermore, we explored the damage degree of cell membrane by various characterizations to prove the thorough death of E. coli. It is desired that this work can offer some inspiration to develop more progressive photocatalytic systems by multiple effects engineering. Combing the merits of 2D ZnIn2S4 nanosheets and CoB nanoparticals, a novel photocatalyst with synergistic effect including Schottky junction and S vacancy engineering was fabricated via a simple electrostatic self-assembly method. Due to the difference in work functions between ZnIn2S4 and CoB, the upward band bending results in the directional flow of the photo-generated electrons from ZnIn2S4–S to CoB, and inhibits the electrons backflow. Meanwhile, S vacancies can capture electrons to boost charge-carriers separation. The efficient charge-carriers separation stimulates the generation of more reactive oxygen species (ROS). Finally, ROS and photo-generated h+ act synergistically on the cell membrane of E. coli, leading to the irreversible death of these cells. [Display omitted] •CoB/ZIS-S photocatalyst with Schottky junction and vacancy engineering was successfully fabricated.•DFT calculation reveals the charge transfer mechanism of photocatalytic reaction.•The establishment of Schottky barrier in CB/ZIS-S can effectively inhibit the backflow of electrons.•CoB/ZIS-S displays excellent performance for photocatalytic E. coli inactivation.