Tuning of the photocatalytic activity of thin titanium dioxide coatings by highly ordered structure and silver nanoparticles

Highly ordered two-dimensional porous TiO2 coatings (HOP) were obtained using the sol gel method and polystyrene (PS) template arranged by self-assembly. The size of the obtained pores was 302 nm, which is less than the size of the PS beads used as a template (320 nm), due to material shrinkage during calcination. Non-ordered porous (NOP) and non-porous (NP) TiO2 coatings were prepared for comparative experiments. XRD analysis revealed that coatings calcined at 500 degrees C are built of anatase phase, while FT-IR measurement confirmed the complete removal of the template after calcination. It was found that the size of silver nanoparticles (AgNPs) grown on the TiO2 surface by the photoreduction of Ag+ ions under UV illumination is comparable for HOP and NP coatings: d = 26 +/- 12 nm and d = 28 +/- 11 nm, respectively. The size of AgNPs grown on NOP coatings was just d = 9 +/- 5 nm. The kinetics of rhodamine B (RhB) photodegradation in aqueous solution was monitored in the presence of HOP and NOP TiO2 coatings, and compared to coatings containing AgNPs. It was found that the best photocatalytic performance was exhibited by coatings with ordered porosity doped with AgNPs. (C) 2016 Elsevier Inc. All rights reserved.