In situ derivation of sulfur activated TiO2 nano porous layers through pulse-micro arc oxidation technology

Micro arc oxidation technique, as a facile and efficient process, was employed to grow sulfur doped titania porous layers. This research sheds light on the photocatalytic performance of the micro arc oxidized S-TiO2 nano-porous layers fabricated under pulse current. Morphological and topographical studies, performed by SEM and AFM techniques, revealed that increasing the frequency and/or decreasing the duty cycle resulted in formation of finer pores and smoother surfaces. XRD and XPS results showed that the layers consisted of anatase and rutile phases whose fraction was observed to change depending on the synthesis conditions. The highest anatase relative content was obtained at the frequency of 500 Hz and the duty cycle of 5%. Furthermore, photocatalytic activity of the layers was examined by measuring the decomposition rate of methylene blue under both ultraviolet and visible photo irradiations. Maximum photodegradation reaction rate constants over the pulse-grown S-TiO2 layers were respectively measured as 0.0202 and 0.0110 min−1 for ultraviolet and visible irradiations.

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► S-TiO2 layers were grown by MAO technique under pulse current for the first time.
► Effect of growth parameters on chemical composition, topography, and morphology of the layers was studied.
► A correlation between photocatalytic performance and growth conditions was proposed.