Green Synthesis of TiO2 Nanoparticles in a Deep Eutectic Solvent for High‐Performance Photocatalysis: The Role of the Cosolvent

• Published in: ChemistrySelect (Weinheim) 2023-04, Vol.8 (13), p.n/a
• Main Authors: Guzmán‐Cruz, Andrés, Lourdes Ruiz‐Peralta, Ma, Pal, Umapada, Paraguay‐Delgado, F., Pal, Mou
• Format: Article
• Language: English
• Subjects: Cosolvent effect; Deep eutectic solvent; Mesoporous TiO2; Photocatalysis; Physicochemical properties
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202300185

Herein, we report a unique surfactant‐free synthetic pathway for the synthesis of anatase TiO2 catalysts in the size range of 13 to 20 nm by solvothermal method using choline chloride‐urea deep eutectic solvent (DES) as green media and 2‐propanol as cosolvent. The composition of reline was tuned by adding 0 (pure reline), 5, 10, 20 and 50 wt% of 2‐propanol. The amount of cosolvent was found to have a significant influence on TiO2 particle size, N2 isotherms and the magnitude of Urbach energy formed within the band gap of mesoporous TiO2 nanostructures. The sample obtained with 10 wt% of propanol showed the best photocatalytic activity in the degradation of Rhodamine B (RhB), which is attributed to the combined effect of Urbach tail states, specific surface area, particle size and band gap energy of TiO2 NPs. Radical trapping experiments with scavengers revealed that OH⋅ radicals are primarily responsible for RhB decomposition. Enhanced photocatalytic performance of mesoporous TiO2 nanoparticles produced by 10 wt% cosolvent addition in deep eutectic solvent by solvothermal synthesis. The improved photoactivity is attributed to the combined effect of Urbach tail states, specific surface area, particle size and band gap energy of TiO2 NPs.