TiO2 nanoparticles coated with deep eutectic solvents: characterization and effect on photodegradation of organic dyes

Abstract

Deep eutectic solvents (DES) have been used as sustainable media for the synthesis of more efficient nanoparticle-based catalysts. However, the effects of DES deposition on the catalytic activity of metal oxide nanoparticles like TiO₂ are unknown. Thus, the goal of this study was to facilitate the deposition of DES onto TiO₂ surfaces and investigate how this coating modulates the catalytic activity of TiO₂ in the photodecomposition of organic dyes. Results for the thermal and spectroscopic properties of the TiO₂ coated with DES in relation to pure materials indicated interactions between these two materials, confirming the deposition of DES onto the TiO₂ surface. Different choline chloride : HBD molar ratios had little impact on the thermal stability, phase transitions, crystallization and amorphization of the mixture. In general, the catalytic activity of TiO₂ coated with DES was reduced. However, TiO₂ covered with ChCl : malonic acid (1 : 2) showed the best catalytic activity and it was better as greater the amount of DES used in the surface deposition.