ALUMINUM–α-HEMATITE THIN FILMS FOR PHOTOELECTROCHEMICAL APPLICATIONS

Abstract

In recent years, photoelectrochemical (PEC) based devices have become attractive due to production of hydrogen by splitting water using photocatalyst alpha ([Formula: see text])-hematite (Fe2O3) as an electrode material due to its bandgap, low cost, chemical stability and extreme abundance in nature. The [Formula: see text]-Fe2O3 is also related to low carrier diffusion due to higher resistivity, slow surface kinetics, low electron mobility and higher electro–hole combination. The carrier mobility and carrier diffusion properties of [Formula: see text]-Fe2O3 have been enhanced by doping as well as composite formation. Keeping in view the enhanced properties of [Formula: see text]-Fe2O3, attempt is being made to dope and form composite using trivalent “aluminum” ions. The Al–[Formula: see text]-Fe2O3 nanophotocatalytic materials were synthesized by varying the ratio of Al to [Formula: see text]-Fe2O3 using sol–gel technique. The nanomaterials “[Formula: see text]-Fe2O3 and Al–[Formula: see text]-Fe2O3” were physically characterized through X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and UV–visible techniques, respectively. The diffusion coefficient of nanomaterials at the electrode/electrolyte interface was analyzed using electrochemical analysis. Interestingly, the presence of aluminum causes the [Formula: see text]-Fe2O3 to change the structural, optical and morphological properties of nanomaterials. The bandgaps of [Formula: see text]-Fe2O3 vary from 2.2[Formula: see text]eV to 2.45[Formula: see text]eV due to presence of aluminum in the structure. The photocurrent studied on Al–[Formula: see text]-Fe2O3 based electrode clearly shows the enhanced hydrogen production under photoelectrochemical cell.