Hollow TiO₂–SiO₂ Nanospheres for Photocatalytic Degradation of Organic Dyes

Abstract

Water pollution is a serious problem in both developed and developing countries. Several methods have been used to purify wastewater, among which photocatalytic decomposition is widely used to purify organic pollutants in wastewater. In this work, hollow nanospheres of titanium dioxide TiO 2 were first prepared by the carbon sphere template method and sol–gel method, and then, the hollow nanospheres of titanium dioxide (TiO 2 ) were compounded with silicon dioxide (SiO 2 ) by the impregnation method to generate complexes with different ratios of hollow nanoparticles of titanium dioxide and silicon dioxide. The best degradation performance of the h-TiO 2 /SiO 2 photocatalytic materials was achieved when the ratio of h-TiO 2 to SiO 2 used was 5:1. The cyclic decomposition efficiency of the 5:1 h-TiO 2 /SiO 2 composites showed only a slight change in the photocatalytic capacity compared to the first cycle, thus ensuring the durability of the samples. However, quenching experiments yielded that hydroxyl radicals play a major role in the degradation process, and possible reaction mechanisms are discussed in detail. The high photocatalytic performance of the environmentally friendly h-TiO 2 /SiO 2 nanosphere photocatalysts makes them ideal for water purification applications and offers potential applications for the utilization of solar energy to effectively reduce environmental pollution. The h-TiO 2 /SiO 2 nanophotocatalysts can not only degrade dyes but can also be valuable for self-cleaning glass applications.