Photoelectrochemical activity of Co-Fe Prussian Blue water oxidation catalyst: operando XAFS.

Metal oxides photoanodes, such as WO3/BiVO4 heterostructures, represent the state of the art towards photoelectrochemical (PEC) water splitting, but their efficiency is still hampered by the sluggish oxygen evolution reaction (OER) kinetics and limited charge separation efficiency. Mixed Cobalt-Iron Prussian Blue (CoFe-PB) was proved to be effective to temper such issues. However, a full comprehension of the catalytic cycle underlying such enhancement is yet to be achieved. Thus, we request beamtime to perform operando photoelectrochemical polarization dependent grazing incidence XAFS measurements, in order to probe the catalyst oxidation state and chemical environment in a fully operating PEC cell, custom designed to allow X-ray fluorescence detection under bias and light stimulation. In this way we will provide a local structural basis for an understanding of the physical properties of this photocatalyst.