Bamboo shoots shaped FeVO4 passivated ZnO nanorods photoanode for improved charge separation/transfer process towards efficient solar water splitting

摘要

Among many novel and promising semiconductors, the triclinic iron vanadate (FeVO4) has been rarely applied in the field of solar water splitting due to its poor charge carrier separation ability. In this work, we prepared FeVO4-passivated ZnO heterojunction nanorods (FVO/ZnO NRs) photoanodes by simple spin-coating and calcination method for the first time. The optimal photoanode exibihits stable and effective PEC water oxidation performance, compared to pristine ZnO, affording 130 mV negative shift in onset potential and 2.4 folds augment in photocurrent density. Particularly, X-ray photoelectron spectroscopy and Mott-Schottky test reveal the establishment of heterojunction, which subdue photo-induced carriers bulk recombination and improve the charge separation efficiency. Open-circuit photovoltage and electrochemical impedance spectroscopy were recorded to further clarify that the FeVO4-passivated layer eliminates the surface trapping state, thus increasing the photovoltage and promoting the interface charge transfer kinetics. These demonstrations are expected to provide new thread for the rational application of new photoanode candidates and to optimize PEC performance.