Realization of Electrochemically Grown a-Fe2O3 Thin Films for Photoelectrochemical Water Splitting Application
Abstract
Hematite ferric oxide (a-Fe2O3) based photoanode has emerged as a potential candidate for water splitting application due to the high absorption coefficient in the visible region and favorable band alignment. In the present work, a-Fe2O3 thin film photoanodes were fabricated using a cost-effective and straightforward electrodeposition technique. The crystal structure, phase purity, elemental composition, and formation of a-Fe2O3 were confirmed by x-ray diffraction (XRD), photoluminescence (PL), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, energy-dispersive x-ray spectroscopy (EDS), and scanning electron microscopy (SEM). The bandgap calculated from the absorption spectrum from UV-visible analysis of a-Fe2O3 exhibits significant absorption in the visible region. The a-Fe2O3 photoanodes were further characterized for their photoelectrochemical (PEC) properties along with electrochemical impedance spectroscopy (EIS) analysis. Furthermore, XRD, SEM, and Fourier transform infrared (FTIR) spectroscopy investigations were performed after photoelectrochemical measurement to ensure the stability of photoanodes. Also, the prepared photoanode is highly stable against a large range of pH conditions, and no photobleaching was observed for up to 30 min. Furthermore, a significant enhancement in photocurrent conversion efficiency with optimum film thickness was observed upon light illumination. A maximum photon conversion efficiency of 1.44 % was obtained with a photocurrent density of 6.25 mA/cm2 for 1 V vs. SCE under simulated solar light.
