Analysis of Metal-Oxide Protected Photoelectrochemical Systems for Water Splitting

Author: Lichterman, Michael Yang

Year: 2018

Degree: Dissertation (Ph.D.)

Advisors: Lewis, Nathan Saul; Gray, Harry B.

Committee Members: Grubbs, Robert H.; Weitekamp, Daniel P.; Brunschwig, Bruce S.; Lewis, Nathan Saul; Gray, Harry B.

Option: Chemistry

DOI: 10.7907/aq89-jv13

Abstract

The photoelectrochemical splitting of water into oxygen and hydrogen gas is one pathway toward the renewable and economic generation of a fuel which is sufficiently scalable to power a large fraction, or even a majority, of the power requirements of modern society. In order to make such a device economically promising, it must be sufficiently cheap, have sufficiently high efficiency, or some combination thereof. In this work, two primary routes toward such a device are discussed; the first is the use of a cheaply prepared photoanode material, BiVO4, the interactions of this material with cobalt oxide based catalysts, and the use of such structures in more extreme pH ranges than have previous been reported. The second route details the application of a protective layer, TiO2, on otherwise unstable materials such as GaP and CdTe when operated as photoanodes in alkaline media. The further work herein applies operando ambientpressure x-ray photoelectron spectroscopy (AP-XPS) to understand the nature of the energetics which allow conduction in the aforementioned TiO2, as well as other energetics in the electrochemical double layer in the adjacent electrolyte. Further experiments using Raman spectroscopy on associated III-V photoanode devices are also described.

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