Effect of TiO<sub>2</sub> Morphology on the Properties and Photocatalytic Activity of g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> Nanocomposites Under Visible-Light Illumination
This study focused on the preparation and investigation of g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> photocatalysts using different TiO<sub>2</sub> morphologies (anatase nanoparticles (TPs), poorly crystalline nanotubes (aTTs), and well-crystalline...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
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| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/3/460 |
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| Summary: | This study focused on the preparation and investigation of g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> photocatalysts using different TiO<sub>2</sub> morphologies (anatase nanoparticles (TPs), poorly crystalline nanotubes (aTTs), and well-crystalline anatase nanorods (TRs)) and self-synthesized g-C<sub>3</sub>N<sub>4</sub> (CN). The synthesis of the g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> composites was carried out using a mortar mixing technique and a g-C<sub>3</sub>N<sub>4</sub> to TiO<sub>2</sub> weight ratio of 1:1. In addition, the g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> composites were annealed in a muffle furnace at 350 °C for 2 h in air. The successful formation of a g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> composite with a mesoporous structure was confirmed using the results of XRD, N2 physisorption, and FTIR analyses, while the results of microscopic analysis techniques confirmed the preservation of TiO<sub>2</sub> morphology in all g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> composites investigated. UV-Vis DR measurements showed that the investigated g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub> composites exhibited visible-light absorption due to the presence of CN. The results of solid-state photoluminescence and electrochemical impedance spectroscopy showed that the composites exhibited a lower charge recombination compared to pure TiO<sub>2</sub> and CN. For example, the charge transfer resistance (RCT) of the CNTR/2 composite of TR and CN calcined in air for 2 h was significantly reduced to 0.4 MΩ, compared to 0.9 MΩ for pure TR and 1.0 MΩ for pure CN. The CNTR/2 composite showed the highest photocatalytic performance of the materials tested, achieving 30.3% degradation and 25.4% mineralization of bisphenol A (BPA) dissolved in water under visible-light illumination. In comparison, the pure TiO<sub>2</sub> and CN components achieved significantly lower BPA degradation rates (between 2.4 and 11.4%) and mineralization levels (between 0.6 and 7.8%). This was due to (i) the presence of Ti<sup>3+</sup> and O-vacancies in the TR, (ii) enhanced heterojunction formation, and (iii) charge transfer dynamics enabled by a dual mixed type-II/Z scheme mechanism. |
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| ISSN: | 1420-3049 |