Visible-light active nanohybrid TiO 2/carbon photocatalysts with programmed morphology by direct carbonization of block copolymer templates

Abstract

Nanopatterned TiO 2/carbon hybrid materials with tailored morphologies were produced by spin-coating solutions of amphiphilic poly(styrene-block-ethylene oxide) (PS-b-PEO) and inorganic precursors followed by sequential stabilization and carbonization. This synthetic strategy is based on cooperative sol-gel chemistry and self-assembly of block copolymers (BCPs), as well as on direct carbonization of the structure-directing BCP templates without additional carbon precursors. Thin films and powders consisting of either TiO 2 dots in carbon matrices or carbon dots in TiO 2 matrices as well as their powder type samples were obtained by varying the ratio of TiO 2 sol-gel precursor to PS-b-PEO. X-ray photoelectron spectroscopy (XPS) revealed the formation of Ti-O-C bonds upon carbonization, as a result of additional electronic states in TiO 2. The latter can be considered as the origin of the band narrowing and visible light absorption. The obtained carbon-TiO 2 nanostructures showed pronounced visible-light photocatalytic activity. © 2011 The Royal Society of Chemistry.