Biotemplated diatom silica–titania materials for air purification

Abstract

We present a novel manufacture route for silica–titania photocatalysts using the diatom microalga Pinnularia sp. Diatoms self-assemble into porous silica cell walls, called frustules, with periodic micro-, meso- and macroscale features. This unique hierarchical porous structure of the diatom frustule is used as a biotemplate to incorporate titania by a sol–gel methodology. Important material characteristics of the modified diatom frustules under study are morphology, crystallinity, surface area, pore size and optical properties. The produced biosilica–titania material is evaluated towards photocatalytic activity for NO_x abatement under UV radiation. This research is the first step to obtain sustainable, well-immobilised silica–titania photocatalysts using diatoms.