Hierarchical SnO₂ nanostructures made of intermingled ultrathin nanosheets for environmental remediation, smart gas sensor, and supercapacitor applications.

In this paper, the hierarchical SnO2 nanostructures (HTNs) were prepared by a facile hydrothermal process. The prepared HTNs were characterized in detail by various analytical techniques that reveal the well-crystallinity with tetragonal rutile structure of SnO2 for the as-prepared material. By detailed experiments, interestingly, it was observed that the shapes and sizes of as-prepared HTNs could be tailored by varying the precursor concentration and reaction time. The synthesized HTNs were used as the efficient photocatalysts for the photocatalytic degradation of methylene blue (MB) under light illumination which showed almost complete degradation (∼99%) of MB dye in 20 min. The observed degradation for MB dye was higher than other commonly used dyes, i.e. methyl orange (MO; 96% in 50 min) and Rhodamine B (RhB; 97% in 40 min.). Further, the prepared HTNs were used as the effective gas sensing material to examine a series of volatile gases, such as ethanol, ammonia, benzene, acetone, toluene, methanol, diethyl ether, and methanol. By the detailed experiments, it was observed that the prepared HTNs exhibited tremendous gas sensing performance toward ethanol. Finally, because of the unique morphology and the fast ion and electron transfer characteristics, the prepared HTNs show excellent supercapacitor performances.