Effect of water ethanol solvents mixture on textural and gas sensing properties of tin oxide prepared using epoxide-assisted sol–gel process and dried at ambient pressure

• High surface area tin oxide aerogel by an ambient pressure drying.
• Epoxide-assisted gelation of non-alkoxide precursor.
• Solvent combinations strongly alter textural properties of tin oxide aerogel.
• Solvent exchange steps in APD process help to minimize impurities.
• CO gas sensing properties improved with an increase in surface area of tin oxide.

High-surface-area tin oxide aerogels have been synthesized by an ambient-pressure drying method, using a non-alkoxide tin precursor and a hybrid sol–gel technique. The tin precursor was dissolved in different volume ratios of mixed water and ethanol solvents, and gelation was attained by means of an epoxide-initiated gelation process. The solvent in the gel was successively replaced with low-surface-tension solvents, and finally the gels were dried at ambient pressure in an oven. It was observed that solvent combinations significantly altered the textural properties of tin oxide aerogels. The solvent exchange process used prior to ambient-pressure drying helped to minimize impurities originating from the tin precursor. The tin oxide aerogels had the maximum specific surface area of 209 m2/g and small crystallite size (<6.5 nm) after an annealing treatment at 500 °C for 2 h. The sensitivity of a SnO2 sensor to CO gas was found to be strongly affected as the specific surface area of its constituent tin oxide aerogel was increased from 121 m2/g to 209 m2/g. This study offers evidence of the effects of tin oxide aerogel's specific surface area upon its gas sensing performance.

High-surface-area tin oxide aerogels have been synthesized by epoxide-assisted sol–gel process followed by an ambient-pressure drying method for 25–100% water solvents mixture and their highly sensitive gas sensing performance was evaluated to be strongly affected by the surface area.Figure optionsDownload as PowerPoint slide