Guest Seminar - One-Dimensional Photoactive Nanostructure Titania for Environmental Pollution Treatment and Clean Energy Production

Photocatalysis is one of the promising methods for capturing the energy from sunlight and converting it into a valuable form of energy such as electricity and fuels. The technology has attracted considerable attention for addressing environmental pollution issues and increasing energy demands at present. In this work, we studied the applications of one-dimensional (1-D) nanostructured TiO2 photocatalyst in the degradation of a water pollutant and the H2 fuel
production, and the development of photocatalyst to improve the performances.

In the first part of this thesis, we studied the use of one-dimensional titanium oxide nanotubes (TiNT) in the photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP). The attractive characteristics of TiNT include the large catalyst surface area and porous structure, the ion-exchange ability, and the surface −OH functional group, which allow further modification or incorporation of other material or dopant. However, the catalyst is inactive under visible light.
We had demonstrated that the doping of copper oxide or iron oxide could improve photocatalytic activity by enhancing visible light absorption and increasing charge separation efficiency.

In the second part of the study, we demonstrated the application of 1-D TiO2 nanowire arrays (TiO2 NWA) for photoelectrochemical (PEC) H2 production. The synthesized TiO2 NWA could generate a much higher photocurrent for water splitting than the commercial P25 TiO2. The outstanding performance was attributed to the larger surface area of the TiO2 NWA and the efficient charge transfer due to the single-crystalline confined structure of the nanowire. The
activity could be further enhanced by forming a heterojunction with a lower band gap graphitic carbon nitride photocatalyst. We also extend our studies towards using the PEC system for CO2 reduction, using copper base electrocatalyst, and proposed the possible approach to make the operation solely rely on solar energy.