Composite photoanodes for artificial leaves

Abstract

In this PhD thesis, Chapter 1 introduces the background and motivation of photoelectrochemical water splitting. Chapter 2 and 3 illustrate the concepts and methodologies to evaluate and understand the effectiveness of photoelectrodes. Chapter 4 includes a comprehensive literature survey of hematite as photoanode material. It is selected as an example to reveal the roles of crystal defects in regard to both bulk and surface properties combining a wide range of research focuses. One type of surface states is identified by examination of experimental results and theoretical predictions over the years. Chapter 5 provides a more in-depth study of the impact of overlayers on hematite photoanodes. Two types of overlayers are investigated here: first, an intrinsically grown amorphous iron oxide layer (FeOx) that is introduced by addition of lactic acid in the precursor formation step; second, one of the most efficient transition metal (oxy)hydroxide oxygen evolution catalyst, CoFeOx coated by electrodeposition. The electrodes are examined using multiple PEC techniques, including PEC impedance spectroscopy, transient photocurrent spectroscopy and intensity modulated photocurrent spectroscopy. Chapter 6 explores a simple way of fabricating nanostructured WO3 photoanodes. We studied the oxide growth in the process of anodization in citric acid solution, along with the influence of morphology on photoactivity. Finally, Chapter 7 concludes this PhD work and gives perspectives for future research.

Date of Award	29 May 2019
Original language	English
Awarding Institution	University of Bath
Supervisor	Davide Mattia (Supervisor), Salvador Eslava Fernandez (Supervisor) & Petra Cameron (Supervisor)