Hematite nanofibers based photoanode for effective photoelectrochemical water oxidation

Sacrificial template-assisted iron(III) oxide (Fe2O3) nanofibers have been prepared by simple electrospinning process on the surface of fluorine-doped tin dioxide (FTO) substrate and used as an efficient photoanode in photoelectrochemical water splitting. The Fe2O3 nanofibers with different thicknesses were obtained on FTO substrate by electrospinning of composite polycaprolactone-FeCl3 (0.16 g of FeCl3 in 10 ml of 15 % PCL solution) at different time durations (3, 5, 7, and 9 h). The systematic study on crystallinity, morphology, specific surface area, and charge recombination process of the photoanodes was performed. The high optical absorbance and band-gap energy were observed for the Fe2O3 photoanodes prepared from 5 h electrospun fibers on the FTO surface (E-spin Fe2O3 NFs@FTO/5 h). The Nyqust plots and Mott-Schottky plots of electrochemical impedance spectroscopy measurements were validated that E-spin Fe2O3 NFs@FTO/5 h photoanode suppresses the charge recombination rates, enhances the electron density, and subsequently improves the performance of photoelectrochemical water splitting. The E-spin Fe2O3 NFs@FTO/5 h photoanode has attained the highest photocurrent density of 0.25 mAcm−2 at 1.23 V vs. RHE applied potential. Moreover, the prepared photoanodes were well attributed to the nanofiber morphology with high crystallinity and, thus, increased the optical absorption rate with improved charge transport properties.