Preparation of nanostructured p-NiO/n-Fe2O3 heterojunction and study of their enhanced photoelectrochemical water splitting performance

•Heterojunction p-NiO/ n-Fe2O3 nanostructure is prepared by solution method with enhanced phtotelectrochemical water splitting performance.•NiO nanoparticles are uniformly covered on vertically oriented α-Fe2O3 nanoflakes with an average size of 20 nm.•NiO/α-Fe2O3 heterojunction exhibits the maximum photocurrent density of 1.55 mA/cm2 at 1 V/RHE.

The n-type α-Fe2O3 nanoflakes are deposited on the FTO substrate by a hydrothermal method and modified with p-type NiO nanoparticles to enhance the photoelectrochemical water splitting performance. X-ray diffraction, field emission scanning electron microscopy, UV–visible and impedance spectroscopy analysis are carried out to study the structural, morphological, and electrochemical characteristics. Formation of p–n heterojunction is confirmed by an impedance spectroscopy analysis and explains the transport of charge carriers. NiO/α-Fe2O3 heterojunction thin film shows the enhancement in photocurrent density (1.55 mA/cm2) compared to the α-Fe2O3 nanoflakes alone (0.08 mA/cm2) under simulated solar radiation at applied potential 1V/RHE.