Defective Black TiO<sub>2</sub>: Effects of Annealing Atmospheres and Urea Addition on the Properties and Photocatalytic Activities
A series of black TiO<sub>2</sub> with and without the addition of urea were successfully prepared using a simple one-step synthetic method by calcination under different atmospheres (vacuum, He, or N<sub>2</sub>). The physicochemical, optical, and light-induced charge transf...
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MDPI AG
2021-10-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/11/10/2648 |
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| author | Xu Zhang Min Cai Naxin Cui Guifa Chen Guoyan Zou Li Zhou |
| author_facet | Xu Zhang Min Cai Naxin Cui Guifa Chen Guoyan Zou Li Zhou |
| author_sort | Xu Zhang |
| collection | DOAJ |
| description | A series of black TiO<sub>2</sub> with and without the addition of urea were successfully prepared using a simple one-step synthetic method by calcination under different atmospheres (vacuum, He, or N<sub>2</sub>). The physicochemical, optical, and light-induced charge transfer properties of the as-prepared samples were characterized by various techniques. It was found that a vacuum atmosphere was more beneficial for the formation of oxygen vacancies (OVs) than the inert gases (He and N<sub>2</sub>) and the addition of urea-inhibited OVs formation. The samples annealed in the vacuum condition exhibited better visible-light adsorption abilities, narrower bandgaps, higher photo-induced charge separation efficiency, and lower recombination rates. Hydroxyl radicals (·OH) were the dominant oxidative species in the samples annealed under a vacuum. Finally, the samples annealed under vacuum conditions displayed higher photocatalytic activity for methylene blue (MB) degradation than the samples annealed under He or N<sub>2</sub>. Based on the above, this study provides new insights into the effects of annealing atmospheres and urea addition on the properties of black TiO<sub>2</sub>. |
| first_indexed | 2024-03-10T06:19:27Z |
| format | Article |
| id | doaj.art-ae5f5cc7090a41428e36c3f686dce6a3 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-10T06:19:27Z |
| publishDate | 2021-10-01 |
| publisher | MDPI AG |
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| series | Nanomaterials |
| spelling | doaj.art-ae5f5cc7090a41428e36c3f686dce6a32023-11-22T19:24:33ZengMDPI AGNanomaterials2079-49912021-10-011110264810.3390/nano11102648Defective Black TiO<sub>2</sub>: Effects of Annealing Atmospheres and Urea Addition on the Properties and Photocatalytic ActivitiesXu Zhang0Min Cai1Naxin Cui2Guifa Chen3Guoyan Zou4Li Zhou5Institute of Eco-Environmental and Plant Protection, Shanghai Academy of Agricultural Sciences, Shanghai 201403, ChinaInstitute of Eco-Environmental and Plant Protection, Shanghai Academy of Agricultural Sciences, Shanghai 201403, ChinaInstitute of Eco-Environmental and Plant Protection, Shanghai Academy of Agricultural Sciences, Shanghai 201403, ChinaInstitute of Eco-Environmental and Plant Protection, Shanghai Academy of Agricultural Sciences, Shanghai 201403, ChinaInstitute of Eco-Environmental and Plant Protection, Shanghai Academy of Agricultural Sciences, Shanghai 201403, ChinaInstitute of Eco-Environmental and Plant Protection, Shanghai Academy of Agricultural Sciences, Shanghai 201403, ChinaA series of black TiO<sub>2</sub> with and without the addition of urea were successfully prepared using a simple one-step synthetic method by calcination under different atmospheres (vacuum, He, or N<sub>2</sub>). The physicochemical, optical, and light-induced charge transfer properties of the as-prepared samples were characterized by various techniques. It was found that a vacuum atmosphere was more beneficial for the formation of oxygen vacancies (OVs) than the inert gases (He and N<sub>2</sub>) and the addition of urea-inhibited OVs formation. The samples annealed in the vacuum condition exhibited better visible-light adsorption abilities, narrower bandgaps, higher photo-induced charge separation efficiency, and lower recombination rates. Hydroxyl radicals (·OH) were the dominant oxidative species in the samples annealed under a vacuum. Finally, the samples annealed under vacuum conditions displayed higher photocatalytic activity for methylene blue (MB) degradation than the samples annealed under He or N<sub>2</sub>. Based on the above, this study provides new insights into the effects of annealing atmospheres and urea addition on the properties of black TiO<sub>2</sub>.https://www.mdpi.com/2079-4991/11/10/2648black TiO<sub>2</sub>annealing atmosphereureaoxygen vacancyphotocatalytic activity |
| spellingShingle | Xu Zhang Min Cai Naxin Cui Guifa Chen Guoyan Zou Li Zhou Defective Black TiO<sub>2</sub>: Effects of Annealing Atmospheres and Urea Addition on the Properties and Photocatalytic Activities Nanomaterials black TiO<sub>2</sub> annealing atmosphere urea oxygen vacancy photocatalytic activity |
| title | Defective Black TiO<sub>2</sub>: Effects of Annealing Atmospheres and Urea Addition on the Properties and Photocatalytic Activities |
| title_full | Defective Black TiO<sub>2</sub>: Effects of Annealing Atmospheres and Urea Addition on the Properties and Photocatalytic Activities |
| title_fullStr | Defective Black TiO<sub>2</sub>: Effects of Annealing Atmospheres and Urea Addition on the Properties and Photocatalytic Activities |
| title_full_unstemmed | Defective Black TiO<sub>2</sub>: Effects of Annealing Atmospheres and Urea Addition on the Properties and Photocatalytic Activities |
| title_short | Defective Black TiO<sub>2</sub>: Effects of Annealing Atmospheres and Urea Addition on the Properties and Photocatalytic Activities |
| title_sort | defective black tio sub 2 sub effects of annealing atmospheres and urea addition on the properties and photocatalytic activities |
| topic | black TiO<sub>2</sub> annealing atmosphere urea oxygen vacancy photocatalytic activity |
| url | https://www.mdpi.com/2079-4991/11/10/2648 |
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