Sol-gel auto-combustion synthesis of Ca2Fe2O5 brownmillerite nanopowders and thin films for advanced oxidation photoelectrochemical water treatment in visible light

Abstract This study describes a straightforward Ca2Fe2O5 brownmillerite nanopowder and thin film synthesis by the water-based sol-gel auto-combustion method. The material characterization results confirmed the phase pure narrow bandgap Ca2Fe2O5 nanoparticle formation. The surface area of synthesized nanopowder was 13.55 m2/g. Powders at loading 1 g/l exhibit high visible light photocatalytic activity by degrading 10 mg/l methylene blue in water in 120 min confirmed by total organic carbon studies. The high visible light photocatalytic activity is related to Ca2Fe2O5 narrow band gap and high reduction potential of its conduction band which triggers the formation of superoxide radical ∙ O 2 -…