In situ growth of SnO2 nanosheets on a substrate via hydrothermal synthesis assisted by electrospinning and the gas sensing properties of SnO2/polyaniline nanocomposites

Abstract

We report a facile method for the in situ growth of vertically aligned SnO₂ nanosheets on a substrate, which involved the hydrothermal treatment of the substrate covered with electrospun nanofibers of poly(vinyl butyral) containing SnCl₂ at low temperatures and free of additives. The formation mechanism of nanostructured SnO₂ has been explored. Gas sensors based on the composites of SnO₂ nanosheets and polyaniline were prepared by vapor phase polymerization of aniline or the dip coating with water-processable polyaniline, and revealed good contact between the sensing films and underlying electrode. The nanocomposite sensors demonstrate very high response magnitude toward NH₃ (relative resistance change of ∼3700% towards 10.7 ppm of NH₃), ultra-low detection limit (∼46 ppb), good sensing repeatability and excellent selectivity at room temperature. Investigations on the gas sensing mechanism of the nanocomposite suggest that the establishment of the p/n heterojunction at the interface of p-type PANI and n-type SnO₂ play an important role in enhancing the response magnitude of the nanocomposite. The method could provide new solutions for the direct fabrication of optoelectronic and electrochemical devices based on nanostructured metal oxides and their composites.