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

Thi-Phuong-Thao Vu; Dinh-Trinh Tran; Viet-Cuong Dang

doi:10.1016/j.jcis.2021.12.050

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

J Colloid Interface Sci. 2022 Mar 15:610:49-60. doi: 10.1016/j.jcis.2021.12.050. Epub 2021 Dec 9.

Authors

Thi-Phuong-Thao Vu¹, Dinh-Trinh Tran², Viet-Cuong Dang¹

Affiliations

¹ VNU Key Lab. of Advanced Materials for Green Growth, University of Science, Vietnam National University, Hanoi, No. 19 Le Thanh Tong street, Hoan Kiem, Hanoi 120000, Vietnam.
² VNU Key Lab. of Advanced Materials for Green Growth, University of Science, Vietnam National University, Hanoi, No. 19 Le Thanh Tong street, Hoan Kiem, Hanoi 120000, Vietnam. Electronic address: trinhtd@vnu.edu.vn.

PMID: 34920216
DOI: 10.1016/j.jcis.2021.12.050

Abstract

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.

Keywords: Dyes; Kinetics, mechanism; N,C,S tri-doped TiO(2); Visible light; WO(3); Z-scheme photocatalyst; rGO.