A versatile bio-inspired material platform for catalytic applications: micron-sized “buckyball-shaped” TiO2 structures

Abstract

A simple sol–gel synthesis method is presented for the production of micron-sized buckyball-like TiO₂ architectures using naturally occurring Lycopodium clavatum (LC) spores as biotemplates. We demonstrate that by simply altering the calcination temperature and titanium(IV) isopropoxide : ethanol volume ratio, the crystal structure and surface composition of the buckyball-like TiO₂ overlayer can be readily fine-tuned. After the removal of the biological scaffold, the unique surface morphology and pore structure of the LC biotemplate can be successfully transferred to the inorganic TiO₂ overlayer. We also utilize photocatalytic degradation of Rhodamine B dye samples to demonstrate the photocatalytic functionality of these micron-sized buckyball-like TiO₂ architectures. Moreover, we show that the photocatalytic activity of TiO₂ overlayers can be modified in a controlled manner by varying the relative surface coverages of anatase and rutile domains. These results open a potential gateway for the synthesis of a variety of bio-inspired materials with unique surface properties and shapes comprised of reducible metal oxides, metal sulfides, mixed-metal oxides, and/or perovskites.