Effect of Decoration of C@TiO 2 Core-Shell Composites with Nano-Ag Particles on Photocatalytic Activity in 4-Nitrophenol Degradation.

Photoactive TiO₂ materials based on a C@TiO₂ core-shell structure synthesized according to the bottom-up strategy using a spherical resin core were presented in relation to commercial TiO₂ (P25) used as a reference material. The studied TiO₂ materials were modified with Ag nanoparticles using two alternative methods: impregnation and precipitation. Depending on the deposition technique used, different distributions of the Ag modifier were achieved within the TiO₂ structure. As confirmed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements, the precipitation technique resulted in the formation of almost twice smaller, highly dispersed Ag nanoparticles compared to impregnation. Furthermore, the effect of the performed modification on the textural properties (low-temperature N₂ adsorption) and surface composition (X-ray photoelectron spectroscopy) was determined. The phase composition of the TiO₂ support as well as the dispersion of the Ag modifier significantly affected the energy gap determined from UV–Vis spectra and, consequently, their performance in the process photodegradation of 4-nitrophenol tested as a model molecule. In the case of the @TiO₂ material modified with highly dispersed Ag, significantly higher photoactivity in the visible light range was observed than in the presence of analogous P25-based materials. [ABSTRACT FROM AUTHOR]