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: Matevž Roškarič, Gregor Žerjav, Janez Zavašnik, Matjaž Finšgar, Albin Pintar
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/30/3/460
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author Matevž Roškarič
Gregor Žerjav
Janez Zavašnik
Matjaž Finšgar
Albin Pintar
author_facet Matevž Roškarič
Gregor Žerjav
Janez Zavašnik
Matjaž Finšgar
Albin Pintar
author_sort Matevž Roškarič
collection DOAJ
description 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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spelling doaj-art-7457c00c7ef4443a8d3dc7030f37234e2025-08-20T02:12:28ZengMDPI AGMolecules1420-30492025-01-0130346010.3390/molecules30030460Effect 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 IlluminationMatevž Roškarič0Gregor Žerjav1Janez Zavašnik2Matjaž Finšgar3Albin Pintar4Department of Inorganic Chemistry and Technology, National Institute of Chemistry, Hajdrihova ulica 19, SI-1001 Ljubljana, SloveniaDepartment of Inorganic Chemistry and Technology, National Institute of Chemistry, Hajdrihova ulica 19, SI-1001 Ljubljana, SloveniaGaseous Electronics, Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, SloveniaFaculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova ulica 17, SI-2000 Maribor, SloveniaDepartment of Inorganic Chemistry and Technology, National Institute of Chemistry, Hajdrihova ulica 19, SI-1001 Ljubljana, SloveniaThis 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.https://www.mdpi.com/1420-3049/30/3/460visible-light photocatalysisg-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub>TiO<sub>2</sub> morphologydual mixed type-II/Z-schemephotocatalytic degradation of bisphenol A
spellingShingle Matevž Roškarič
Gregor Žerjav
Janez Zavašnik
Matjaž Finšgar
Albin Pintar
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
Molecules
visible-light photocatalysis
g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub>
TiO<sub>2</sub> morphology
dual mixed type-II/Z-scheme
photocatalytic degradation of bisphenol A
title 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
title_full 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
title_fullStr 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
title_full_unstemmed 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
title_short 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
title_sort 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
topic visible-light photocatalysis
g-C<sub>3</sub>N<sub>4</sub>/TiO<sub>2</sub>
TiO<sub>2</sub> morphology
dual mixed type-II/Z-scheme
photocatalytic degradation of bisphenol A
url https://www.mdpi.com/1420-3049/30/3/460
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