TiO2-nanoparticles-impregnated photocatalytic macroporous carbon films by spin coating

Abstract

Macroporous TiO2/polyacrylonitrile (PAN) and TiO2/carbon hybrid films are fabricated directly by spin coating. Macroporosity is promoted under the conditions favoring the growth of instabilities and dewetting of the spin-coated films such as lower film thicknesses, higher evaporation rates and lower molecular weights (viscosity). The synthesis of the hybrid film is achieved by a two-step process. First, TiO2 powder mixed with PAN in N, N-dimethyl formamide (DMF) solvent is cast as a thin film on a silicon wafer by spin coating. Second, heat treatment at 900°C produces pure rutile TiO2 nanocrystals and concurrently pyrolyzes PAN to a porous glassy carbon matrix. The resultant TiO2/carbon hybrid porous films exhibit excellent photocatalytic activity as shown for the degradation of Rhodamine B dye in aqueous medium.