Optimized thin films composed of ZnO nanorods, grown after preliminary electrodeposition and successively coated with 3 layers of TiO2 and decorated with Ag2Se nanoparticles, were prepared onto glass FTO wafers to treat oxytetracycline solutions by photoelectrocatalysis (PEC). The coatings were thoroughly characterized by XRD, Raman and UV/Vis diffuse reflectance spectroscopy, confocal microscopy, FE-SEM, HRTEM, EDX and XPS. The synthesized films had a mean thickness of 1.19 mu m, length >500 nm and a bandgap of 1.85 eV, being visible-light photoactive. Good stability and reproducibility was obtained when treating 5 mg dm(-3) oxytetracycline solutions in 0.050 M Na2SO4 at pH 5.8, attaining 96.5% antibiotic decay after 360 min at an anodic potential of +1.0 V vs Ag vertical bar AgCl under irradiation with a 36-W blue LED lamp. Comparative photocatalysis and electrochemical oxidation treat...

Here, we demonstrate the viability of a ZnO/TiO2/Ag2Se thin-film composite synthesized on FTO to degrade the drug naproxen in aqueous solutions by visible-light photoelectrocatalysis (PEC). The experiments were made with 100 mL of solutions containing 5 mg L-1 drug and 50 mM Na2SO4 at natural pH, using a cell equipped with a Pt wire as cathode and the composite as photoanode exposed to a 36 W blue LED lamp. Total degradation was achieved after 210 min of electrolysis at anodic potential of +1.0 V/Ag vertical bar AgCl. This resulted from the oxidative action of hydroxyl radicals formed via direct anodic water discharge and through mediated water oxidation by photogenerated holes. The degradation rate decreased at higher naproxen concentration, but the treatment efficiency became higher due the deceleration of the parasitic reactions involving hydroxyl radicals. In chloride medium, the pho...