Towards a Rationalization of the Photoelectrochemical Performance of Delafossite Oxides CuRhO\(_{2}\) and AgRhO\(_{2}\)

Abstract

Photoelectrochemical water splitting is an attractive method for generating H2, a renewable fuel. This thesis will discuss two similar photocathode materials used in the hydrogen evolution portion of this process—CuRhO\(_{2}\) and AgRhO\(_{2}\)—which despite their many structural and compositional similarities, have greatly differing performance. AgRhO\(_{2}\)shows less susceptibility to photoreduction than CuRhO\(_{2}\), as well as higher photocurrent density. I will present work towards understanding these differences based on comparisons of the properties of these two materials in several areas: the composition of the states in their photoactive regions, the energetics of their surface states, and their bulk transport properties. These comparisons were performed based on DFT calculations, as well with reference to experimental work. From these comparisons, a number of potential explanations emerge, although all are clouded by conflicting evidence or have yet to be fully experimentally tested.