Interface engineering of nanoceramic hematite photoelectrode for solar energy conversion

This work addresses the role of different modifiers on the overall photocurrent response, which allowed a dual material insertion, increasing the charge separation without compromise the surface catalysis. Sn‐addition onto nanoceramic hematite photoelectrodes clearly increased flat band potential, promoting a good charge separation, and shifting the onset to a higher potential, attributed to the surface‐trapping state created by this modification. Notoriously, Sn‐hematite photoelectrodes loaded with NiFeOx exhibited the highest photocurrent density, suggesting a partially recovered surface‐trapping states created during the electrode designing. The well‐known cocatalyst acted in the overall photoelectrocatalytic response with no significant effect on the turn‐on voltage, in other words, with minor effect related to catalytic efficiency. The dual modification contributes to understand the role of different modifiers allowing to satisfactorily improve charge separation while maintaining the conductivity attributed to IV‐group ions. Decoupling complex parameters on hematite‐based photoanodes turned a challenge on using this material for water splitting reactions. In this recent work, it has been shown that dual elemental insertion (Sn and FeNiOx) seems promisor to maintain the electronic conductivity on bulk structure, while partially mitigate the charge transfer recombination on the solid‐liquid interface, increasing the efficiency.