Characterization and photocatalytic properties of tungsten doped TiO2 coatings on aluminum obtained by plasma electrolytic oxidation

Abstract

This paper presents a recent investigation of rapid deposition of TiO2 nanoparticles on aluminum by plasma electrolytic oxidation in Na2SiO3 center dot 5H(2)O water based electrolyte with addition of TiO2 nanoparticles and Na2WO4 center dot 2H(2)O. Oxide coatings were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and grazing incidence X-ray diffraction. It was found that surface morphology, chemical and phase compositions of obtained coatings depend on electrolyte composition and processing time. The photocatalytic activity was tested by photodegrading methyl orange under simulated sunlight conditions. It was observed that photodegradation of methyl orange strongly depends on the concentration of TiO2 nanoparticles and sodium tungstate in the electrolyte and PEO treatment time. Coatings with the highest photoactivity were obtained in 4 g/L Na2SiO3 center dot 5H(2)O + 2 g/L Degussa P25 + 0.1 g/L Na2WO4 center dot 2H(2)O.