CAS: Revealing the Atomic and Electronic Structures of the Photoelectrode/Catalyst/Water Interfaces and Their Effects on Solar Water Splitting

With the support of the Chemical Catalysis Program in the Division of Chemistry, Professor Kyoung-Shin Choi of the University of Wisconsin-Madison and Professor Giulia Galli of the University of Chicago are studying semiconductor electrodes that can utilize solar energy to split water and produce hydrogen gas, a clean fuel. These electrodes are called photoelectrodes, and their overall performance is affected considerably by their surface composition and structure.

Using combined experimental and computational approaches, Choi and Galli aim to obtain a microscopic understanding of how the surface composition and structure of a photoelectrode affect the interfaces of the photoelectrode, the catalyst coating, and the surrounding water. They will then investigate how these interfacial structures influence the device-level performance.

These studies are expected to have broad scientific impact, informing the rational design of optimal interfaces for efficient solar water splitting. In addition, as part of this project, Professors Choi and Galli will make tutorials on how to validate theoretical structural models and on how to compare theoretical and experimental results in a robust manner.

This will enhance the infrastructure available for guiding other researchers studying solar water splitting and related systems using similar approaches. This project will also train graduate students in a highly interdisciplinary environment and generate versatile researchers in the field of clean fuel production using renewable solar energy. The project will broadly benefit society by building fundamental scientific knowledge toward the sustainable production of clean fuel.

With the support of the Chemical Catalysis program in the Division of Chemistry, Professor Kyoung-Shin Choi of the University of Wisconsin-Madison and Professor Giulia Galli of the University of Chicago are studying photoelectrodes that can utilize solar energy to split water and produce hydrogen gas, a clean fuel. The overall goals of their study are to elucidate the atomic details of the impact that the surface and interface of photoelectrodes have on their photoelectrochemical properties using tightly integrated experimental and computational investigations and to establish interface-photoelectrochemical property relationships.

Using V-rich and Bi-rich BiVO4 (010) epitaxial photoelectrodes, Choi and Galli have previously demonstrated that the surface composition/structure can remarkably affect the surface energetics and photoelectrochemical properties of BiVO4 even for the same (010) facet. Using these experimentally and computationally well-understood V-rich and Bi-rich BiVO4 (010) surfaces, the PIs will investigate how the surface composition and structure affect the atomic and electronic structures at the BiVO4/oxygen evolution catalyst (OEC), BiVO4/water, and BiVO4/OEC/water interfaces.

Then, the same types of interfaces will be formed using V-rich and Bi-rich BiVO4 with a different exposed facet to extract the general effects of the surface composition that are independent of the facet type. This project will provide a microscopic understanding of how the surface composition and structure of a photoelectrode affect the photoelectrode/OEC/water interface and the device-level performance beyond the typical phenomenological studies and understanding of photoelectrode surfaces and interfaces.

These studies will address critical questions in the solar fuel field and have the potential to greatly enable the design of optimal interfaces for efficient solar water splitting, an outcome that would be a key advancement in the quest to build out new clean energy technologies.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.