ISBN 978-3-8439-3597-5

978-3-8439-3597-5, Reihe Elektrotechnik

Xiaodan Wang
Tuning the Photoelectrochemical Functionality of CoreShell H-doped Titania Nanorods by Hydrogen Surface Engineering

151 Seiten, Dissertation Technische Universität Braunschweig (2017), Softcover, A5

Zusammenfassung / Abstract

Photoelectrochemical (PEC) solar water splitting is an efficient and low-cost method to produce clean hydrogen fuel from solar energy and water. A nanostructured semiconducting photoanode is a key component in the PEC cell to determine the photocatalytic performance. TiO2 is the most widely investigated semiconducting material, however, the solar-to-hydrogen efficiency of TiO2 is limited due to its wide band gap and low conductivity. In 2011 a new form of “TiO2”, namely black TiO2, has been realized by high-pressure hydrogenation of anatase TiO2 nanocrystals (Chen et al. Science 2011, 331, 746). Due to its unique optical and electrical properties, black TiO2 has triggered research interest worldwide. However, more experimental characterization and theoretical simulation are required to comprehensively understand the nature of black TiO2, and more efficient hydrogenation approaches are needed to further improve its photocatalytic performance. Till now all reported hydrogenation approaches are performed under severe technical conditions like high temperature or pressure, prolonged treatment time or high doses of hydrogen. Therefore, new hydrogenation approaches with the mild condition are required. Due to the high power hydrogenation, the degradation issues of FTO (F:SnO2) conducting substrate and strong structure destruction of H-TiO2 cannot be addressed. Also the processing – structural – optical – photoelectrochemical properties relationship is rarely reported in the literature.

The goal of this thesis was to develop new mild hydrogenation methods and treat 3D TiO2 nanorods for the photoelectrochemical application. The new three surface engineering of TiO2 nanorods are performed by rapid thermal annealing (RTA), hot wire annealing (HWA) and the room temperature hydrogen plasma annealing (RT-HPA) respectively. Which showed improved photoelectrochemical behavior of H-TiO2 nanorods. In addition, I systematically studied the processing - structural - optical - PEC property relationship to understand the physical insight of enhanced PEC performance.

This research might provide new insights into synthesis, microstructure, optical and PEC properties of H-TiO2, which can be used as a scientific basis for the development of high-performance energy storage and conversion devices