Enhanced Photocatalytic Performance of Nitrogen-Doped TiO<sub>2</sub> Nanotube Arrays Using a Simple Annealing Process
Nitrogen-doped TiO<sub>2</sub> nanotube arrays (N-TNAs) were successfully fabricated by a simple thermal annealing process in ambient N<sub>2</sub> gas at 450 °C for 3 h. TNAs with modified morphologies were prepared by a two-step anodization using an aqueous NH<sub>4&l...
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doaj-5418ea3d0ebd4b819e54bae10cf0a0a32020-11-24T21:41:36ZengMDPI AGMicromachines2072-666X2018-11-0191261810.3390/mi9120618mi9120618Enhanced Photocatalytic Performance of Nitrogen-Doped TiO<sub>2</sub> Nanotube Arrays Using a Simple Annealing ProcessPhuoc Huu Le0Le Trung Hieu1Tu-Ngoc Lam2Nguyen Thi Nhat Hang3Nguyen Van Truong4Le Thi Cam Tuyen5Pham Thanh Phong6Jihperng Leu7Ceramics and Biomaterials Research Group, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City 700000, VietnamDepartment of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30049, TaiwanDepartment of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30049, TaiwanFaculty of Natural Sciences, Thu Dau Mot University, 6 Tran Van On Street, Thu Dau Mot City 820000, VietnamFaculty of Fundamental Sciences, Thai Nguyen University of Technology, Thai Nguyen 24000, VietnamCeramics and Biomaterials Research Group, Advanced Institute of Materials Science, Ton Duc Thang University, Ho Chi Minh City 700000, VietnamFaculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City 700000, VietnamDepartment of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30049, TaiwanNitrogen-doped TiO<sub>2</sub> nanotube arrays (N-TNAs) were successfully fabricated by a simple thermal annealing process in ambient N<sub>2</sub> gas at 450 °C for 3 h. TNAs with modified morphologies were prepared by a two-step anodization using an aqueous NH<sub>4</sub>F/ethylene glycol solution. The N-doping concentration (0–9.47 at %) can be varied by controlling N<sub>2</sub> gas flow rates between 0 and 500 cc/min during the annealing process. Photocatalytic performance of as-prepared TNAs and N-TNAs was studied by monitoring the methylene blue degradation under visible light (λ ≥ 400 nm) illumination at 120 mW·cm<sup>−2</sup>. N-TNAs exhibited appreciably enhanced photocatalytic activity as compared to TNAs. The reaction rate constant for N-TNAs (9.47 at % N) reached 0.26 h<sup>−1</sup>, which was a 125% improvement over that of TNAs (0.115 h<sup>−1</sup>). The significant enhanced photocatalytic activity of N-TNAs over TNAs is attributed to the synergistic effects of (1) a reduced band gap associated with the introduction of N-doping states to serve as carrier reservoir, and (2) a reduced electron‒hole recombination rate.https://www.mdpi.com/2072-666X/9/12/618N-doped TNAstwo-step anodizationphotocatalytic activitythermal annealingmodified TiO<sub>2</sub>band gap |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Phuoc Huu Le Le Trung Hieu Tu-Ngoc Lam Nguyen Thi Nhat Hang Nguyen Van Truong Le Thi Cam Tuyen Pham Thanh Phong Jihperng Leu |
spellingShingle |
Phuoc Huu Le Le Trung Hieu Tu-Ngoc Lam Nguyen Thi Nhat Hang Nguyen Van Truong Le Thi Cam Tuyen Pham Thanh Phong Jihperng Leu Enhanced Photocatalytic Performance of Nitrogen-Doped TiO<sub>2</sub> Nanotube Arrays Using a Simple Annealing Process Micromachines N-doped TNAs two-step anodization photocatalytic activity thermal annealing modified TiO<sub>2</sub> band gap |
author_facet |
Phuoc Huu Le Le Trung Hieu Tu-Ngoc Lam Nguyen Thi Nhat Hang Nguyen Van Truong Le Thi Cam Tuyen Pham Thanh Phong Jihperng Leu |
author_sort |
Phuoc Huu Le |
title |
Enhanced Photocatalytic Performance of Nitrogen-Doped TiO<sub>2</sub> Nanotube Arrays Using a Simple Annealing Process |
title_short |
Enhanced Photocatalytic Performance of Nitrogen-Doped TiO<sub>2</sub> Nanotube Arrays Using a Simple Annealing Process |
title_full |
Enhanced Photocatalytic Performance of Nitrogen-Doped TiO<sub>2</sub> Nanotube Arrays Using a Simple Annealing Process |
title_fullStr |
Enhanced Photocatalytic Performance of Nitrogen-Doped TiO<sub>2</sub> Nanotube Arrays Using a Simple Annealing Process |
title_full_unstemmed |
Enhanced Photocatalytic Performance of Nitrogen-Doped TiO<sub>2</sub> Nanotube Arrays Using a Simple Annealing Process |
title_sort |
enhanced photocatalytic performance of nitrogen-doped tio<sub>2</sub> nanotube arrays using a simple annealing process |
publisher |
MDPI AG |
series |
Micromachines |
issn |
2072-666X |
publishDate |
2018-11-01 |
description |
Nitrogen-doped TiO<sub>2</sub> nanotube arrays (N-TNAs) were successfully fabricated by a simple thermal annealing process in ambient N<sub>2</sub> gas at 450 °C for 3 h. TNAs with modified morphologies were prepared by a two-step anodization using an aqueous NH<sub>4</sub>F/ethylene glycol solution. The N-doping concentration (0–9.47 at %) can be varied by controlling N<sub>2</sub> gas flow rates between 0 and 500 cc/min during the annealing process. Photocatalytic performance of as-prepared TNAs and N-TNAs was studied by monitoring the methylene blue degradation under visible light (λ ≥ 400 nm) illumination at 120 mW·cm<sup>−2</sup>. N-TNAs exhibited appreciably enhanced photocatalytic activity as compared to TNAs. The reaction rate constant for N-TNAs (9.47 at % N) reached 0.26 h<sup>−1</sup>, which was a 125% improvement over that of TNAs (0.115 h<sup>−1</sup>). The significant enhanced photocatalytic activity of N-TNAs over TNAs is attributed to the synergistic effects of (1) a reduced band gap associated with the introduction of N-doping states to serve as carrier reservoir, and (2) a reduced electron‒hole recombination rate. |
topic |
N-doped TNAs two-step anodization photocatalytic activity thermal annealing modified TiO<sub>2</sub> band gap |
url |
https://www.mdpi.com/2072-666X/9/12/618 |
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