Synthesis of Cobalt-Doped SnO 2 Nanoparticles by Chemical Precipitation with Chelation.

The greenness of a chemical precipitation process was attempted in the synthesis of SnO2nanoparticles through the use of safe, environmental-benign citric acid as a chelating agent. Thermogravimetric analysis (TGA) of the precipitates was used to study thermal decomposition. Presence of functional groups was examined by Fourier Transform Infrared Spectroscopy (FTIR). Negligible traces of functional groups were detected after calcination at 800°C. Phase formation and the degree of crystallinity were probed by X-ray diffraction (XRD). The process with chelation by citric acid resulted in larger crystallite sizes compared to those from the non-chelated system. The morphology of the nanoparticles was investigated by transmission electron microscopy (TEM). Although the SnO2phase could not be obtained at ambient temperature due to oxidative constraint, chelation by citric acid did indeed reduce the calcination temperature required for the change in the oxidation number and thus emergence of the SnO2phase. Such results could be indicative of lessened energy requirement in the synthesis of SnO2nanoparticles. [ABSTRACT FROM AUTHOR]