Spray deposited Fe₂O₃ photoelectrode for degradation of benzoic acid and methyl blue dye under solar radiation

Spray pyrolysis technique is used for the preparation of Fe₂O₃ thin films onto glass and fluorine doped tine oxide (FTO) coated glass substrates. The effect of thickness (Fe₂O₃ film) on to structural, optical, morphological, compositional and photocatalytic properties of films are studied. All the deposited Fe₂O₃ films are polycrystalline with rhombohedral crystal structures. The maximum photoelectrochemical performance [short circuit current density (J_sc = 0.206 mA) and open circuit voltage (V_oc = 262 mV)] is observed for the film deposited at 1.56 µm thickness. The morphological study shows that the different sizes of grain are randomly distributed on the surfaces of the film and its size increases with respect to thickness of the film. The estimated band gap energy of Fe₂O₃ thin films varies between 2.01 and 2.21 eV. Photocatalytic and photoelectrocatalytic degradation experiment is carried out with the help of large area (10 × 10 cm²) deposited Fe₂O₃ photoelectrode for degradation of benzoic acid (BA) and methyl blue (MB) dye under solar illumination. There is 56.6 and 90.7% of BA and MB dye degraded in 320 and 120 min respectively using photoelectrocatalytic degradation method. The mineralization of BA and MB dye in aqueous solution are studied by measuring chemical oxygen demand (COD) values. The observed result indicates that Fe₂O₃ photoelectrode is useful for degradation of BA and MB dye from wastewater.