Novel N,C,S-TiO2/WO3/rGO Z-scheme heterojunction with enhanced visible-light driven photocatalytic performance

• Published in: Journal of colloid and interface science Vol. 610; pp. 49 - 60
• Main Authors: Vu, Thi-Phuong-Thao, Tran, Dinh-Trinh, Dang, Viet-Cuong
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.03.2022
• Subjects: Dyes; Kinetics, mechanism; N,C,S tri-doped TiO2; rGO; Visible light; WO3; Z-scheme photocatalyst; Z-scheme photocatalyst; Kinetics, mechanism; Dyes; N,C,S tri-doped TiO2; Visible light; WO3; rGO
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2021.12.050

[Display omitted] •Novel N,C,S-TiO2/WO3/rGO Z scheme photocatalyst generates both O2•- and HO• under visible light irradiation.•Electron-hole recombination rate is reduced due to Z-scheme system and graphene sheets.•Dye degradation is significantly enhanced by N,C,S-TiO2/WO3/rGO photocatalyst.•Dye degradation process is impacted by reaction conditions, and follows the pseudo-first-order kinetics model.•N,C,S-TiO2/WO3/rGO could be easily regenerated and reused with high photocatalytic performance. Novel N,C,S-TiO2/WO3/rGO Z scheme photocatalyst was successfully synthesized from graphite, TIOT, and ammonium metatungstate precursors. Material characteristics such as crystal structure, surface morphology, functional groups, specific surface area, elemental composition, band gap energy, and electron-hole recombination were characterized by XRD, TEM, BET, SEM/EDX, FT-IR, UV–VIS, and PL methods. The as-synthesized novel N,C,S-TiO2/WO3/rGO Z-scheme heterojunction photocatalyst exhibited visible light-driven photocatalytic activity (the band gap energy = 2.24 eV), could generate both effective electrons and holes, and presented the lowest electron-hole recombination rate compared to all individual components. Different factors impacting the photocatalytic decomposition of Direct Blue 71 (DB 71) by the N,C,S-TiO2/WO3/rGO system were studied. The results showed that pH of the solution, catalyst load, DB 71 initial concentration, and reaction time affected the DB 71 photocatalytic degradation efficiency. The DB 71 degradation completed after 100 min with a typical efficiency of over 91%, which was much better than other photocatalytic systems. The DB 71 degradation process followed the pseudo-first-order kinetics model with coefficients of determination > 0.95 for all conditions. The photocatalyst was easily regenerated, and exhibited a very good stability, with a photocatalytic degradation efficiency of over 83.0% after 3 cycles.