The effect of surface modification with Ag nanoparticles on 21 nm TiO2: anatase/rutile material for application in photocatalysis

Abstract

The purpose of this article is to present a perspective, environmentally friendly, and cost-effective chemical approach for preparing photocatalysts that can be used in wastewater treatment. One nanometer-sized Ag nanoparticles (NPs) were deposited on the surface of a commercial titanium dioxide mixture of anatase and rutile. A novel low-temperature chemical method using an ultrasonication process without a reducing agent was applied to surface-modified TiO2 grains with Ag NPs. The materials were characterized by several complementary techniques, such as X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV–Vis diffuse reflectance (DRS), Raman spectroscopy, X-ray electron spectroscopy (XPS), Mott-Schottky analysis, and N2 adsorption-desorption measurements. The silver content in the prepared samples ranged from 0.1 to 0.5 wt% (low Ag content) and from 1 to 5 wt% (high Ag content). The photocatalytic performance of the pristine and Ag NPs modified TiO2 powders in photodegradation of the acid orange 7 model dye was studied under ultraviolet (UV), visible (Vis) and UV + Vis radiation. This study explores, for the first time, a photodegradation mechanism for all combinations of wavelengths and silver contents, which is of practical importance in selecting the best photocatalyst and irradiation conditions.