Effect of Decoration of C@TiO2 Core-Shell Composites with Nano-Ag Particles on Photocatalytic Activity in 4-Nitrophenol Degradation

Abstract

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.