Investigation of the structural, optical, and photoelectrochemical properties of α-Fe2O3 nanorods synthesized via a facile chemical bath deposition

Abstract

In this study, a simple and cost-effective chemical bath deposition was employed to deposit nan-sized hematite (α-Fe2O3) directly on fluorine-doped tin oxide (FTO) substrates. The structure, morphology, and optical properties of α-Fe2O3 were manipulated by adjusting the experimental parameters, particularly the deposition temperature and precursor concentration. With increase in Fe precursor concentration from 0.1 M to 0.3 M, the surface morphology was changed from granular-shape condensed particles to vertically aligned rod-like structures. XRD spectra indicated signals from FTO substrate and pure α-Fe2O3 phase which corresponds to the rhombohedral system. The XPS analysis revealed the presence of α-Fe2O3 in the film and no tin (Sn) impurities from the FTO substrate. By changing the deposition temperature from 60 ℃ to 90 ℃, the size of particles increased; whereas, the surface morphology was not altered. The resultant films were examined as photoanode for photoelectrochemical (PEC) water splitting. The optimized electrode exhibited maximum water splitting photocurrent density of 700 μA.cm−2 at 1.6 V versus reversible hydrogen electrode (RHE) under simulated solar illumination (AM 1.5, 100 mW.cm−2) in 1 M NaOH. This could be attributed to the large electrode electrolyte interfacial area and low charge transfer resistance offered by nanorods of α-Fe2O3 of high surface-to-volume ratio.