Applied Potential Effect on ZnFe2O4-Fe2O3 Heterostructure for Generation of Photocurrents under Irradiation

Abstract

In this study, the performance of ZnFe2O4-Fe2O3 heterostructure was tested for photocurrent generation via photoelectrochemical activity under irradiation. Additionally, the effect of heterostructure photoanode on the structural, optical properties, and charge kinetic behavior of the photoelectrode was investigated. A combination of ZnFe2O4-Fe2O3 nanostructures exhibited an enhanced ability of light absorption compared to that of pristine Fe2O3 and ZnFe2O4 samples. For ZnFe2O4-Fe2O3 nanostructures, an electron–hole transfer resistance of 9.41 kΩ was achieved in a 0.1 M KOH electrolyte under irradiation, which is much lower than that of achieved values of pure Fe2O3 and ZnFe2O4 nanostructures. The generation of photocurrent density of ZnFe2O4-Fe2O3 photoanode considerably increased in 0.1 M KOH electrolytes under irradiation compared to those of the other samples due to the greater active sites, electronic band structure, absorption capability of photoanode, and considerable improvements in the charge transfer resistance, limiting current density, exchange current density, and Tafel slope. Further, the applied potential showed a strong significant influence on the generation of photocurrent for the synthesized photoelectrodes. At 0.5 V applied potential, the heterostructure showed a maximum and enhanced current density compared to pristine samples. Thus, ZnFe2O4-Fe2O3 photoanodes were established to be beneficial and stable nanostructures for photoelectrochemical water splitting.