Macro-/mesoporous titania thin films: analysing the effect of pore architecture on photocatalytic activity using high-throughput screening

Abstract

Hierarchically porous, anatase titania thin films were fabricated by a one-pot, soft-templating technique combined with a phase separation route. The pore structure was readily tuned by adjusting the concentration of the polymeric components added during the sol–gel synthesis. Poly(vinylpyrrolidone) (PVP) altered the three dimensional pore structure, generating macroporous networks within the films. The effect of the morphological modifications on the photocatalytic activity of titania was investigated by the photodegradation of methylene blue using high-throughput screening, with the macroporous arrangement of the films significantly influencing photocatalytic activity. The highest photocatalytic activity under UV irradiation normalised by the accessible surface area was obtained by porous titania thin films prepared using 1:1:0 poly(ethylene glycol):PVP:Pluronic® F127. The addition of F127 did increase the overall photocatalytic activity, but lowered the activity per unit area because of obstructed light penetration. These results provide insight into the effect of regulating the pore morphology of titania thin films to further enhance their potential as immobilised photocatalytic reactors.