Tungsten Oxide Morphology-Dependent Au/TiO<sub>2</sub>/WO<sub>3</sub> Heterostructures with Applications in Heterogenous Photocatalysis and Surface-Enhanced Raman Spectroscopy
Developing highly efficient Au/TiO<sub>2</sub>/WO<sub>3</sub> heterostructures with applications in heterogeneous photocatalysis (photocatalytic degradation) and surface-enhanced Raman spectroscopy (dye detection) is currently of paramount significance. Au/TiO<sub>2<...
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MDPI AG
2023-06-01
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| author | István Székely Zoltán Kovács Mihai Rusu Tamás Gyulavári Milica Todea Monica Focșan Monica Baia Zsolt Pap |
| author_facet | István Székely Zoltán Kovács Mihai Rusu Tamás Gyulavári Milica Todea Monica Focșan Monica Baia Zsolt Pap |
| author_sort | István Székely |
| collection | DOAJ |
| description | Developing highly efficient Au/TiO<sub>2</sub>/WO<sub>3</sub> heterostructures with applications in heterogeneous photocatalysis (photocatalytic degradation) and surface-enhanced Raman spectroscopy (dye detection) is currently of paramount significance. Au/TiO<sub>2</sub>/WO<sub>3</sub> heterostructures were obtained via heat or time-assisted synthesis routes developed by slightly modifying the Turkevich–Frens synthesis methods and were investigated by TEM, SEM, XRD, Raman spectroscopy, XPS, photoluminescence, and UV–vis DRS techniques. Structural features, such as WO<sub>3</sub> crystalline phases, TiO<sub>2</sub> surface defects, as well as the WO<sub>3</sub> (220) to TiO<sub>2</sub>-A (101) ratio, were the key parameters needed to obtain heterostructures with enhanced photocatalytic activity for removing oxalic acid, phenol, methyl orange, and aspirin. Photodegradation efficiencies of 95.9 and 96.9% for oxalic acid; above 96% (except one composite) for phenol; 90.1 and 97.9% for methyl orange; and 81.6 and 82.1% for aspirin were obtained. By employing the SERS technique, the detection limit of crystal violet dye, depending on the heterostructure, was found to be between 10<sup>−7</sup>–10<sup>−8</sup> M. The most promising composite was Au/TiO<sub>2</sub>/WO<sub>3</sub>-HW-TA it yielded conversion rates of 82.1, 95.9 and 96.8% for aspirin, oxalic acid, and phenol, respectively, and its detection limit for crystal violet was 10<sup>−8</sup> M. Au/TiO<sub>2</sub>/WO<sub>3</sub>-NWH-HA achieved 90.1, 96.6 and 99.0% degradation efficiency for methyl orange, oxalic acid, and phenol, respectively, whereas its limit of detection was 10<sup>−7</sup> M. The Au/TiO<sub>2</sub>/WO<sub>3</sub> heterojunctions exhibited excellent stability as SERS substrates, yielding strong-intensity Raman signals of the pollutant molecules even after a long period of time. |
| first_indexed | 2024-03-11T02:40:05Z |
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| id | doaj.art-c134593a308642e6ab46d94588cc27a8 |
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| last_indexed | 2024-03-11T02:40:05Z |
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| spelling | doaj.art-c134593a308642e6ab46d94588cc27a82023-11-18T09:42:30ZengMDPI AGCatalysts2073-43442023-06-01136101510.3390/catal13061015Tungsten Oxide Morphology-Dependent Au/TiO<sub>2</sub>/WO<sub>3</sub> Heterostructures with Applications in Heterogenous Photocatalysis and Surface-Enhanced Raman SpectroscopyIstván Székely0Zoltán Kovács1Mihai Rusu2Tamás Gyulavári3Milica Todea4Monica Focșan5Monica Baia6Zsolt Pap7Doctoral School of Physics, Babes-Bolyai University, M. Kogălniceanu 1, 400084 Cluj-Napoca, RomaniaDoctoral School of Physics, Babes-Bolyai University, M. Kogălniceanu 1, 400084 Cluj-Napoca, RomaniaCentre of Nanostructured Materials and Bio-Nano Interfaces, Institute for Interdisciplinary Research on Bio-Nano-Sciences, Treboniu Laurian 42, 400271 Cluj-Napoca, RomaniaDepartment of Applied and Environmental Chemistry, University of Szeged, Rerrich Sqr. 1, HU-6720 Szeged, HungaryCentre of Nanostructured Materials and Bio-Nano Interfaces, Institute for Interdisciplinary Research on Bio-Nano-Sciences, Treboniu Laurian 42, 400271 Cluj-Napoca, RomaniaNanobiophotonics and Laser Microspectroscopy Center, Interdisciplinary Research Institute on Bio-Nano-Sciences, Babes-Bolyai University, Treboniu Laurian 42, 400271 Cluj-Napoca, RomaniaCentre of Nanostructured Materials and Bio-Nano Interfaces, Institute for Interdisciplinary Research on Bio-Nano-Sciences, Treboniu Laurian 42, 400271 Cluj-Napoca, RomaniaCentre of Nanostructured Materials and Bio-Nano Interfaces, Institute for Interdisciplinary Research on Bio-Nano-Sciences, Treboniu Laurian 42, 400271 Cluj-Napoca, RomaniaDeveloping highly efficient Au/TiO<sub>2</sub>/WO<sub>3</sub> heterostructures with applications in heterogeneous photocatalysis (photocatalytic degradation) and surface-enhanced Raman spectroscopy (dye detection) is currently of paramount significance. Au/TiO<sub>2</sub>/WO<sub>3</sub> heterostructures were obtained via heat or time-assisted synthesis routes developed by slightly modifying the Turkevich–Frens synthesis methods and were investigated by TEM, SEM, XRD, Raman spectroscopy, XPS, photoluminescence, and UV–vis DRS techniques. Structural features, such as WO<sub>3</sub> crystalline phases, TiO<sub>2</sub> surface defects, as well as the WO<sub>3</sub> (220) to TiO<sub>2</sub>-A (101) ratio, were the key parameters needed to obtain heterostructures with enhanced photocatalytic activity for removing oxalic acid, phenol, methyl orange, and aspirin. Photodegradation efficiencies of 95.9 and 96.9% for oxalic acid; above 96% (except one composite) for phenol; 90.1 and 97.9% for methyl orange; and 81.6 and 82.1% for aspirin were obtained. By employing the SERS technique, the detection limit of crystal violet dye, depending on the heterostructure, was found to be between 10<sup>−7</sup>–10<sup>−8</sup> M. The most promising composite was Au/TiO<sub>2</sub>/WO<sub>3</sub>-HW-TA it yielded conversion rates of 82.1, 95.9 and 96.8% for aspirin, oxalic acid, and phenol, respectively, and its detection limit for crystal violet was 10<sup>−8</sup> M. Au/TiO<sub>2</sub>/WO<sub>3</sub>-NWH-HA achieved 90.1, 96.6 and 99.0% degradation efficiency for methyl orange, oxalic acid, and phenol, respectively, whereas its limit of detection was 10<sup>−7</sup> M. The Au/TiO<sub>2</sub>/WO<sub>3</sub> heterojunctions exhibited excellent stability as SERS substrates, yielding strong-intensity Raman signals of the pollutant molecules even after a long period of time.https://www.mdpi.com/2073-4344/13/6/1015heterostructuresaspirintoxic pollutantsphotocatalytic activityAu NPscrystal violet |
| spellingShingle | István Székely Zoltán Kovács Mihai Rusu Tamás Gyulavári Milica Todea Monica Focșan Monica Baia Zsolt Pap Tungsten Oxide Morphology-Dependent Au/TiO<sub>2</sub>/WO<sub>3</sub> Heterostructures with Applications in Heterogenous Photocatalysis and Surface-Enhanced Raman Spectroscopy Catalysts heterostructures aspirin toxic pollutants photocatalytic activity Au NPs crystal violet |
| title | Tungsten Oxide Morphology-Dependent Au/TiO<sub>2</sub>/WO<sub>3</sub> Heterostructures with Applications in Heterogenous Photocatalysis and Surface-Enhanced Raman Spectroscopy |
| title_full | Tungsten Oxide Morphology-Dependent Au/TiO<sub>2</sub>/WO<sub>3</sub> Heterostructures with Applications in Heterogenous Photocatalysis and Surface-Enhanced Raman Spectroscopy |
| title_fullStr | Tungsten Oxide Morphology-Dependent Au/TiO<sub>2</sub>/WO<sub>3</sub> Heterostructures with Applications in Heterogenous Photocatalysis and Surface-Enhanced Raman Spectroscopy |
| title_full_unstemmed | Tungsten Oxide Morphology-Dependent Au/TiO<sub>2</sub>/WO<sub>3</sub> Heterostructures with Applications in Heterogenous Photocatalysis and Surface-Enhanced Raman Spectroscopy |
| title_short | Tungsten Oxide Morphology-Dependent Au/TiO<sub>2</sub>/WO<sub>3</sub> Heterostructures with Applications in Heterogenous Photocatalysis and Surface-Enhanced Raman Spectroscopy |
| title_sort | tungsten oxide morphology dependent au tio sub 2 sub wo sub 3 sub heterostructures with applications in heterogenous photocatalysis and surface enhanced raman spectroscopy |
| topic | heterostructures aspirin toxic pollutants photocatalytic activity Au NPs crystal violet |
| url | https://www.mdpi.com/2073-4344/13/6/1015 |
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