Novelties in synthesis of unsupported and crack-free titania membranes from metal alkoxides using two-way controllable sol–gel method

Abstract

A novel approach has been developed to synthesize unsupported titania membranes by two-way controllable sol–gel method wherein polyvinyl alcohol (PVA) was used as a cost effective additive. Defect-free unsupported titania membranes were prepared using controlled hydrolysis by precursor modification and controlled gelation by addition of an organic binder. A suitable concentration of PVA was determined to produce minimum stress and form stable unsupported titania membrane. The optimized concentration of PVA (11.52 wt%) resulted in the formation of self-supported membrane with stable and reproducible textural properties like surface uniformity, larger surface area (118 m²/g) and smaller pore size (9.9 nm). Addition of PVA leads to the deceleration of transformation from anatase to rutile phase and formation of crack-free titania membrane having higher crystallinity. The membranes are fully characterized and will find many applications.