Understanding Photoelectrochemical Water Oxidation with X-ray Absorption Spectroscopy

Synchrotron radiation-based X-ray absorption spectroscopy (XAS) has been demonstrated to be a powerful and effective characterization tool in comprehensively and deeply understanding the photoelectrochemical (PEC) water splitting process owing to its unique capability in probing the electronic structure changes of photoelectrodes. In this review, we present the most recent achievements in the past few years of synchrotron XAS techniques for the advanced investigation of hematite and other commonly used photoanodes. By focusing on the unique and powerful roles that XAS played in identifying the chemical compositions and exploring the working mechanism of various photoanodes, we will provide an in-depth understanding on how the XAS technique can guide the design of efficient photoanodes and contribute to the further development of PEC water splitting. The review is also expected to stimulate more interests of the PEC society, in general, in taking advantage of XAS to facilitate their research.