Physico-chemical property-driven dielectric behaviour and catalytic activity of nanocrystalline mullite synthesized from monophasic precursor gel

Nanocrystalline mullite was synthesized from single-phase mullite precursor with occurrence of mullite phases at 550 A degrees C which is very low compared to traditional mullitization temperatures. Microstructural study showed uniform nanosized grains (20 nm) forming spherical aggregates at lower temperatures with equiaxed grains of mullite formed from the mullite seeds via nucleation and growth at 1400 A degrees C. Frequency-dependent dielectric properties of nanosized mullite have been investigated related to sintering temperature, amount of mullite, porosity and grain size of mullite. The mullite nanocrystals were also an efficient catalyst in Biginelli reaction which is a multicomponent assembly process under solvent-free condition. Mechanistic growth of nanocrystalline mullite from a single-phase sol-gel precursor with its physico-chemical property-dependent dielectric behaviour and catalytic activity. [GRAPHICS] .