Details

Autor(en) / Beteiligte

• Székely, István
• Kovács, Zoltán
• Rusu, Mihai
• Gyulavári, Tamás
• Todea, Milica
• Focșan, Monica
• Baia, Monica
• Pap, Zsolt

Titel

Tungsten Oxide Morphology-Dependent Au/TiO[sub.2]/WO[sub.3] Heterostructures with Applications in Heterogenous Photocatalysis and Surface-Enhanced Raman Spectroscopy

Ist Teil von

• Catalysts, 2023-06, Vol.13 (6)

Ort / Verlag

MDPI AG

Erscheinungsjahr

2023

Quelle

Electronic Journals Library

Beschreibungen/Notizen

• Developing highly efficient Au/TiO[sub.2]/WO[sub.3] heterostructures with applications in heterogeneous photocatalysis (photocatalytic degradation) and surface-enhanced Raman spectroscopy (dye detection) is currently of paramount significance. Au/TiO[sub.2]/WO[sub.3] 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] crystalline phases, TiO[sub.2] surface defects, as well as the WO[sub.3] (220) to TiO[sub.2]-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]-10[sup.−8] M. The most promising composite was Au/TiO[sub.2]/WO[sub.3]-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] M. Au/TiO[sub.2]/WO[sub.3]-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] M. The Au/TiO[sub.2]/WO[sub.3] heterojunctions exhibited excellent stability as SERS substrates, yielding strong-intensity Raman signals of the pollutant molecules even after a long period of time.