Titanium (IV) oxide composite hollow nanofibres with silver oxide outgrowth by combined sol–gel and electrospinning techniques and their potential applications in energy and environment

Abstract

A two-dimensional nanostructure composed of Ag2O nanobranches attached to TiO2 hollow nanofibres (denoted as 2D Ag2O/TiO2) was successfully prepared via sol–gel and coaxial electrospinning techniques. The Ag/TiO2 hollow nanofibres were fabricated and calcined in ambient air at 500 °C. By calcination, the removal of organic materials and the formation of anatase TiO2 were achieved with a well-retained hollow structure. The embedded Ag nanoparticles functioned as seeds for the Ag2O outgrowth on the TiO2 surface using a hydrothermal treatment at different times and temperatures, which caused the change in physical appearance, surface area, and electrical conductivity of 2D Ag2O/TiO2. A high quantity of Ag2O nanobranches on TiO2 nanofibres were obtained with increasing the temperature from 110 to 115 °C and the reaction time to 60 min. Consequently, the electrochemical active surface area (EASA) value was maximised to 65.25 cm2 per cm2 with an enhanced electrical conductivity of 91.3 ± 3.9 × 10−2 S cm−1. Further studies on the depth-profiles of Ag, Ti, and O revealed the presence of Ag2O attached to the core structure of TiO2. The photoelectrochemical and photocatalytic tests confirmed the excellent physical and electrochemical properties of 2D Ag2O/TiO2 (@115 °C, 60 min) for use in energy and environmental applications.Graphical