Interface reacted ZnFe2O4 on α-Fe2O3 nanoarrays for largely improved photoelectrochemical activity†
ZnFe2O4/α-Fe2O3 heterojunctions were successfully synthesized by depositing ZnO films on α-Fe2O3 nanorods through the atomic layer deposition technique, followed by annealing in air. The as-fabricated heterostructures showed a significant enhancement in photoelectrochemical (PEC) performance when compared to the bare α-Fe2O3, with photocurrent density increasing from 0.03 mA cm−2 for pristine α-Fe2O3 to 0.29 mA cm−2. The increased photocurrent for the ZnFe2O4/α-Fe2O3 heterojunction was ascribed to the enhanced charge carrier density and the efficient separation of electron–hole pairs at the ZnFe2O4/α-Fe2O3 interface. The significant performance enhancement suggests that the rational design and construction of the heterostructures with suitable band alignment as photoelectrodes are promising to achieve highly efficient PEC water splitting.