Criss-crossed α-Fe2O3 nanorods/Bi2S3 heterojunction for enhanced photoelectrochemical water splitting

In this research work, α-Fe2O3/Bi2S3 heterojunction photoelectrodes for improved photoelectrochemical water splitting have been successfully fabricated on FTO substrate by applying hydrothermal and solvothermal approaches. A seed layer approach is also applied before the solvothermal step for the homogeneous distribution of Bi2S3 over α-Fe2O3 nanorods to obtain a uniform heterojunction. The physicochemical and optical techniques results of α-Fe2O3/Bi2S3 indicate high crystallinity, presence of two distant phases with different bandgap positions. Linear sweep voltammetry (LSV) results indicate that the optimized α-Fe2O3/Bi2S3 photoanode performs a maximum photocurrent density of 2.550 mA cm−2 at 1.23 VRHE which is almost 20 times higher than pristine α-Fe2O3 (0.123 mA cm−2 at 1.23 V RHE). Electrochemical Impedance Spectroscopy (EIS) entirely shows α-Fe2O3/Bi2S3.6 h is the lowest Rp (180.9 Ω cm2) compare to pristine Fe2O3 (5810 Ω cm2), indicating enhanced photocatalytic performance on OER and S2-/S22- cycle followed under 100 mW cm−2 solar irradiation. This significant upsurge in the photocurrent density and applied biased photon-to-current conversion efficiency shown by the heterojunction is attributed to the improved light-harvesting efficiency, enhanced conductivity, and effective charge separation at the α-Fe2O3/Bi2S3 interface.