Exploring FeVO4/ZnCo2O4 n-p heterojunctions for superior photoelectrochemical performance

The lack of suitable charge separation and transport properties limits the applicability of FeVO4 in the field of photoelectrochemical (PEC) water splitting. A study was conducted for the first time to investigate PEC oxygen evolution by fabricating FeVO4/ZnCo2O4 n-p heterojunction using insitu solid transformation followed by dropcoating methods. The successful outcome of this fabrication of the heterojunction has been clarified through different structural, morphological and optical characterizations. When the ZnCo2O4 nanoparticles are optimally deposited over FeVO4, the photocurrent density reaches 0.57 mA cm-2, while the incident photon-to-current efficiency (IPCE) reaches 13 %. The interface between FeVO4 and ZnCo2O4 has been developed to improve carrier separation efficiency by up to 3.3 %. This remarkable achievement also leads to an injection efficiency of 98 %, significantly enhancing the absorption of visible light. The coating of ZnCo2O4 nanoparticles over FeVO4 nanopebble structure also reduces the interfacial resistance that exists between the photoelectrode and electrolyte, in comparison to bare FeVO4 nanopebble. In depth behavior of the FeVO4/ZnCo2O4 composite with respect to FeVO4 that exhibits a unique n-p staggered type-II heterojunction were investigated through MottSchottky and electrochemical spectroscopic characterizations which explains the generation of oxygen vacancies during their fabrication facilitate charge transfer within the system and enhance the efficiency of electron-hole separation.