Role of cobalt in photoelectrochemical oxygen evolution reactions at Fe2O3-CoPi photoelectrodes

This project aims to understand how Fe2O3-CoPi photoelectrodes work for photoelectrochemical water splitting. There are three different models about how cobalt in these electrodes contributes to the reaction, in particular, hole accumulation, participation forming Co(IV) intermediates at the cobalt oxyhydroxide surface and/or additional absorption of light with subsequent shifting of the electronic density from Co to oxygen radical. By measuring small differences in Co and Fe K-edge XAS spectra induced by light modulation in situ at photoelectrochemical conditions we would like to disentangle these mechanisms and find the dominant one. This will help improve the design of these photoelectrodes and find directions for more efficient hydrogen fuel production.