Hierarchical TiO2/Fe2O3 heterojunction photoanode for improved photoelectrochemical water oxidation

A 3D hierarchical TiO2/Fe2O3 heterojunction photoanode with an improved photoelectrochemical (PEC) water splitting performance was successfully prepared by introducing a titanium nitride (TiN) underlayer through electrophoretic deposition route. Compared to that of pristine Fe2O3 photoanode, the photocurrent density of TiO2/Fe2O3 heterojunction at 1.23 V vs. reversible hydrogen electrode (RHE) increased by more than 2.1 times and achieved to 1.79 mA cm(-2). According to X-ray photoelectron Spectrometer (XPS) and electrochemical impedance spectra (EIS) results, the improved PEC water oxidation performance of TiO2/Fe2O3 photoanode can be attributed to the promoted charge separation and transfer due to the construction of 3D hierarchical heterostructure. This work provides a facile strategy to enhance PEC water splitting performance of hematite, which may help for designing efficient hematite photoanodes for practical applications.