Structure-Property Relationships in Redox-Derivatized Metal-Insulator-Semiconductor (MIS) Photoanodes

Metal-insulator-semiconductor (MIS) junctions based on n-Si have proven to be effective electrodes in terms of electrocatalysis activity and durability for performing photoelectrochemical water oxidation. Here, we show that the modification of n-Si MIS systems with CoFe Prussian blue (CoFePB) and NiRu Prussian blue (NiRuPB) analogues can modify their properties and allow a direct probing of the interfacial energetics through their redox feature. Our investigations demonstrate the importance of the preparation route and attribute the large upward photovoltage variation found in n-Si/SiOx/Ni/NiRuPB to the increasing inhomogeneity of the metal thin film. Finally, the optimal photoanode was tested for oxygen evolution and urea oxidation reactions. Our findings provide important insights on MIS photoanodes for future development in the field of solar fuel production.