Functionalization of TiO2 Nanofibers with Ag and Ag2S Nanoparticles for Enhanced Photocatalytic Hydrogen Generation

Abstract

One-dimensional (1D) nanomaterials owing to their unique properties, including semi-directed charge transport, enhanced charge carrier mobility and more active sites, make them intriguing materials for application in photocatalysis. In this work, a simple electrospinning method was used to synthesize 1D TiO2 and TiO2/Ag nanofibers, followed by calcination in air at 500 °C for 2 h to achieve anatase crystalline nanofibers. TiO2/Ag2S composite nanofibers was prepared through hydrothermal treatment of TiO2/Ag nanofibers using Thiourea as the sulfur source for sulfidation. The photocatalytic activities of the as-prepared nanofibers were tested for hydrogen evolution from water with methanol as the sacrificial reagent under the simulated solar irradiation. The results indicate that by incorporating Ag nanoparticles into 1D TiO2 nanofibers largely enhanced the photocatalytic hydrogen evolution with the best Ag nanoparticles loading amount of ~10 at.%. Furthermore, it was found that the efficiency of photocatalytic hydrogen evolution was further improved after sulfidation of TiO2/Ag nanofibers, which indicates that TiO2/Ag2S nanofibers are efficient photocatalyst. Compared with pure TiO2 and TiO2/Ag nanofibers, the TiO2/Ag2S composite nanofibers have the highest photocatalytic activities, and the optimal sulfidation condition was achieved with 150 mg of Thiourea in hydrothermal treatment. The Ag2S nanoparticles have a dual function as improving charge separation and broaden the light absorption spectrum of the photocatalyst. This synthetic methodology described in this work is a promising approach to fabricate nanostructures with high throughput under mild condition for enhanced photocatalytic applications.