A Novel Solvothermal Synthesis of High-Surface-Area SnO₂ Nanocrystals

A novel solvothermal synthesis of high-surface-area SnO₂ nanocrystals with different particle sizes was presented. The synthesis was carried out by a two-step urea-based solvothermal method using SnCl₄·5H₂O as the starting material and ethanol as the solvent in the presence of different concentrations of urea. The obtained SnO₂ nanocrystals at different reaction temperatures were characterized by means of X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), thermo-gravimetry and differential thermal analysis (TG-DTA), and nitrogen BET measurements. The results revealed that by increasing the alkalinity of the precursor solution and decreasing the reaction temperatures, the crystallite sizes of the prepared SnO₂ nanocrystals decreased from 6 nm to 3 nm, while the specific surface area of the prepared powders increased from 114 m²/g to 187 m²/g. The well-dispersed high-surface-area powders are favorable for gas-sensing applications at room temperature.