Enhanced photocatalytic performance and photocorrosion stability of PEO-immobilized TiO2 photocatalyst using rGO/Fe2O3 sensitizers

Abstract

TiO2 photocatalysts containing rGO/Fe2O3 sensitizers were immobilized on titanium supports using the plasma electrolytic oxidation process, and their photocatalytic as well as photocorrosion properties were studied. The characterization proved that the intervention of rGO/Fe2O3 sensitizers in the forming interactions caused the growth of the photocatalyst layer at lower voltages, reducing its thickness, surface roughness, and porosity. Ultraviolet-visible and photoluminescence spectroscopies revealed that with sensitizer embedding, the utilization of the photocatalyst in the visible region of the solar irradiation spectrum significantly improved, and the recombination of the photogenerated charge carriers suppressed. As a result, the photodegradation kinetics of methylene blue solution under 100 W xenon irradiation was promoted by 91.1% compared to the pure TiO2 photocatalyst. The photoelectrochemical evaluation denoted that rGO/Fe2O3 sensitizers had a constructive effect in strengthening the photocorrosion stability of the photocatalyst by removing inherent defects and enhancing the microstructure compactness so that the polarization resistance increased to 3 and 1.5 times that of the pure sample under ambient and xenon lights, respectively. Moreover, the surface reactivity of the sensitized photocatalyst with corrosive species reduced under both lights, as a result of the Mott-Schottky analysis.