Synthesis and characterization of nanometer SnO2 by non-hydrolytic sol-gel approach

Nanometer SnO2 powders were successfully prepared by non-hydrolytic sol-gel approach combined with heat treatments using tin tetrachloride as starting material and ethylene glycol as solvent. The reaction mechanism of the sol-gel process is proposed. Results indicate that the -OHCH2CH2OH- prevent Cl- ion from accessing to tin Sn4+ due to steric effect, and hence increaseing the stability of the sol solution. Ethylene glycol functions not only as a complextion agent to form a polymer network but also as a "spacer" to modulate the distance between metal ions. preventing metal oxide particles from aggregation during desiccation of the sol. The effects of heat treatments on the evolution of structure and morphology of nanosized SnO2 powders were studied. The powders with narrow size distribution around 15 similar to 20 nm could be obtained at 500 degrees C for 4 h.