Photoelectrocatalytic oxidation of Rhodamine B with sprayed α-Fe2O3 photocatalyst

Spray deposited iron oxide thin films have been synthesized using ferric trichloride precursor in ethanolic medium. The effect of deposition temperature onto photochemical, structural, morphological, optical, luminescence and thermal properties has been investigated. Structural analysis confirms alpha-Fe2O3 (hematite) phase with rhombohedral crystal structure. The SEM images of optimized Fe2O3 thin films show needle like structure with varying grain size from 120-250 nm. The observed direct band gap is varying from 2.16 to 2.21 eV with substrate temperature. Room temperature photoluminescence spectra showed three pronounced emission peaks such as, UV near-band-edge emission peak around 380-436 nm, a blue emission around 468 nm, and green emission around 560 nm. The XPS results revealed the presence of Fe3+ in Fe2O3 photoelectrode. The photocatalytic oxidation of Rhodamine B (RhB) with hematite Fe2O3 thin films under solar illumination is investigated. The first order rate constants of photocatalysis are evaluated as a function of the initial concentration of RhB. The extent of mineralization has been studied by analyzing total organic carbon (TOC) and chemical oxygen demand (COD). The estimated values of COD, TOC are decreases from 82 to 9.6 mg/l and 78.7 to 13.9 mg/l respectively.