Nanocomposites and nanomaterials

Effect of PVP molecular weight on the plasma-chemical formation of Ag nanoparticles on TiO2 for enhancing under UV/sunlight photocatalytic degradation of organic dye pollutant

Skiba M.I.1, Vorobyova V.I.2
1 Ukrainian State University of Chemical Technology, 
Gagarinа ave. 8, Dnipro 49005, Ukraine
E-mail: Margaritaskiba88@gmail.com
2National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Peremohy ave. 37, Kyiv 03056, Ukraine

Ag nanoparticles were immobilized on TiO2 particles using plasma-chemical reduction process with poly(vinyl pyrrolidone) (PVP) of different molecular weights. Ag nanoparticles were successfully formed on the TiO2 surface when PVP of different molecular weights were used. Ag NPs were characterized by UV-visible spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The average size of formed Ag NPs is 10-35 nm. XRD analysis revealed that the particles were face-centred cubic. It was found that the size distribution of the Ag NPs proved to be a key factor determining the photodegradation activity of the materials measured using different organic dye. The mechanism for formation of Ag/TiO2 composites which is influenced by the molecular weight of PVP in the system was described. 
Due to formation of Ag (1–2.5 wt%) nanodeposits over TiO2, the hydrodynamic size of Ag-TiO2 composite is increased by 1.3 - 2.7 times relative to bareTiO2 (~250 nm). It was found that the reduction of organic dye by 2 wt% Ag-TiO2 under sunlight irradiation occurred quite efficiently whereas bare TiO2 showed negligible activity under same reaction conditions.

Souza, H.T.S., Oliveira, S.A.A., Souza, J.S. (2020). Modulating the photocatalytic activity of Ag nanoparticles-titanate nanotubes heterojunctions through control of microwave-assisted synthesis conditions // Journal of Photochemistry and Photobiology A: Chemistry, 112264.