Monodisperse-porous titania microspheres and their gold decorated forms as new photocatalysts for dye degradation in batch fashion

Abstract

A new photocatalyst in the form of “monodisperse-porous titania microspheres” 5 μm in size, was synthesized by a developed staged-shape template hydrolysis and condensation protocol. Different from the batch-decolorization studies performed with the “non-porous titania nanoparticles”, a two-stage decolorization process including a fast initial dye adsorption and a relatively slower photodegradation was observed with the proposed photocatalyst. Higher initial decolorization rate was achieved due to the fast dye adsorption onto the porous titania microspheres with higher surface area with respect to “non-porous titania nanoparticles” commonly employed as photocatalyst in similar decolorization studies. Moreover, gold decorated forms of monodisperse-porous titania microspheres were also synthesized. Higher decolorization rates with respect to the bare titania microspheres were achieved with the gold decorated forms at neutral pH. Gold decorated photocatalyst synthesized using gold nanoparticles with lower size provided 50% higher decolorization rate due to their better electron transfer characteristics.