Photoelectrochemical degradation of selected organic substances on Fe2O3 photoanodes: a comparison with TiO2

The photoelectrochemical degradation of selected aromatic substances, acid orange 7 (AO7), salicylic acid (SA), benzoic acid (BA), and 4-chlorophenol (4-CP) was studied on hematite (α-Fe2O3) and compared with titanium dioxide (TiO2), both deposited as thin films on conducting substrates (FTO/glass). Batch type reactors were used under backside and front side illumination. Electrical bias was applied on the semiconducting electrodes, such that only valence band processes leading to oxidative pathways were followed. The initial Faradaic efficiency, f0, of degradation processes was determined from the UV–Vis absorbance decrease of the starting materials. f0 for 1 mM AO7 degradation in 0.01 M sulphuric acid was found to be 7.5