Visible light induced enhanced photocatalytic degradation of organic pollutants in aqueous media using Ag doped hollow TiO2 nanospheres

Abstract

The silver doped hollow TiO₂ (Ag-h-TiO₂) nanoparticles were synthesized by a sacrificial core (AgBr) method. The Ag doping and the core removal was done simultaneously during the dissolution of the core in (NH₄)OH solution. The mean particle size of synthesized Ag-h-TiO₂ nanoparticles is 17.76 ± 2.85 nm with a wall thickness of ∼2.5 nm. The hollow structured nanoparticles have 103.2 m² g⁻¹ more specific surface area compared to solid TiO₂ nanoparticles. The suitability of these synthesized hollow nanoparticles as photocatalyst were tested for the photocatalytic degradation of three important different classes of organic compounds such as nitrobenzene (NB), metronidazole (MTZ) antibiotic, and methylene blue dye (MBD) in aqueous solution under irradiation of visible light. Photodegradation studies show there is a significant enhancement of the degradation efficiency of the TiO₂ after the hollow structure formation and silver doping. The recycling tests of the catalysts show only ∼10% decrease in efficiency for NB and MTZ degradation after sixth cycle of reuse. The light emission capacity in terms of quantum yield (QY) is enhanced by 18.7% for Ag-h-TiO₂ than that of pure TiO₂ nanoparticles.