B, Gd Co-Doped TiO₂ Nanotube Arrays for Efficient Degradation of Gaseous Toluene under Visible Light Irradiation

Abstract

Although photocatalytic degradation of VOCs has attracted widespread attention, the efficient visible-light-driven photocatalytic degradation performance remains a challenge. This work presents the visible-light-driven photocatalytic degradation of gaseous toluene over B, Gd co-doped TiO₂ nanotube arrays prepared via a controllable electrochemistry method. It was found that B and Gd co-doping strategy not only enhances the visible light responsiveness of TiO₂ nanotube arrays but also introduces moderate oxygen vacancies on the surface of TiO_2, which is beneficial to the formation of free hydroxyl radicals and their attack on toluene molecules. The doping order also affects the photocatalytic performance. The optimized sample achieves an enhanced degradation efficiency for toluene under visible light irradiation and exhibits considerable stability. This work may provide an efficient TiO₂-based photocatalyst for the removal of volatile organic compounds for air purification and give an understanding of the mechanism of photocatalytic degradation of toluene over co-doping TiO₂.

Keywords

TiO₂ nanotube array / Photocatalysis / VOCs degradation / Oxygen vacancies / In-suit DRIFTS

Supplementary Materials

The following supporting information can be found at: https://www.sciepublish.com/article/pii/485, Figure S1: Schematic of the sample preparation of B-TNA and Gd-TNA. Figure S2: Performance evaluation system. Figure S3: In-situ infrared diffuse reflection device diagram. Figure S4: TEM and HR-TEM images for (a) B-TNA, (b) Gd-TNA; (c) TEM image of the B-TNA, and the EDX mapping images of its (d) Ti, (e) O, (f) B atoms; (g) TEM image of the Gd-TNA, and the EDX mapping images of its (h) Ti, (i) O, (j) Gd atoms. Figure S5: (a) XPS survey of the B/Gd-TNA, (b) Gd 4d XPS spectra of Gd-TNA, B/Gd-TNA, and Gd/B-TNA. Figure S6: (a) O K-edge and (b) Ti K-edge XANES spectra of the TNA, B-TNA, Gd-TNA, B/Gd-TNA, Gd/B-TNA. Figure S7: (a) B-TNA (B_s), (b) B-TNA(B_i), (c) Gd-TNA, (d) B/Gd-TNA (B_s), (e) B/Gd-TNA (B_i), (f) Gd/B-TNA (B_s), and (g) Gd/B-TNA (B_i) models (The blue, grey, green and pink spheres depict the Ti, O, Gd and B atoms respectively). Figure S8: Photocatalytic degradation activity of gaseous toluene (a) B-TNA, and (b) Gd-TNA. Figure S9: Absorption infrared spectra of toluene over (a) B_1.5/Gd₃-TNA, (b) B₆/Gd₃-TNA, (c) Gd₃/B_1.5-TNA, and (d) Gd₃/B₆-TNA. Figure S10: Spectra of catalytic degradation of toluene with (a) B_1.5/Gd₃-TNA, (b) B₆/Gd₃-TNA, (c) Gd₃/B_1.5-TNA, and (d) Gd₃/B₆-TNA. Table S1: Doping concentration. Table S2: Formation Energy (E_f) of doped system.

Author Contributions

Conceptualization, J.D. and S.S.; Methodology, P.W.; Software, J.G. and F.C.; Validation, S.S.A.S. and T.D.; Formal Analysis, X.W. and J.B.; Investigation, Y.X. and L.G.; Resources, Y.W., M.C.; Writing—Original Draft Preparation, J.D.; Writing—Review & Editing, S.S.; Funding Acquisition, S.S.

Ethics Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Funding

This research was funded by the National Natural Science Foundation of China (21902001, 22179001 and 22308001), Distinguished Young Research Project of Anhui Higher Education Institution (2022AH020007), Higher Education Natural Science Foundation of Anhui Province (2023AH050114, KJ2021A0029 and KJ2021A0027), The University Synergy Innovation Program of Anhui Province (GXXT-2023-009), Anhui Province Engineering Research Center of Critical Electronic Materials, and the High-end Chemicals and Cutting-edge New Materials Technology Innovation Center of Hefei (HCHC202210).

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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