Probing the limits of frequency-modulated operando PEC characterization of charge carriers dynamics in heterostructured photoanodes

Building on previous work at ID26, this proposal aims to further develop and refine Intensity-Modulated X-ray Absorption Spectroscopy (IM-XAS), a novel frequency-resolved technique we pioneered to probe charge transfer kinetics at semiconductor/co-catalyst interfaces. IM-XAS enables real-time tracking of oxidation state changes by monitoring X-ray fluorescence intensity under modulated light excitation. This continuation experiment will optimize IM-XAS to explore higher-frequency charge transfer dynamics by investigating thinner co-catalyst layers, high-performance OER catalysts, and interface engineering strategies such as hole blocking layers and scavengers. These advancements will deepen our understanding of fast charge dynamics, crucial for improving the efficiency of photoelectrochemical (PEC) water splitting, and guide the rational design of next-generation catalyst architectures.