Comparison on gas-sensing properties of single- and multi-layered SnO2 nanostructures in drug-precursors detection

Systematic comparison on gas-sensing properties of single- and multi-layered SnO2 nanomaterials in drug-precursors detection from the aspects of gas-sensing response and kinetic adsorption/desorption process was presented for the first time. The SnO2 nanomaterials with single- and multi-layered structures assembled by numerous nanoparticles were prepared via a hydrothermal route using carbonaceous spheres as templates. In gas-sensing measurements, drug-precursors including aether and chloroform were employed as targets. The gas-sensing responses towards target gases at a series of concentrations were investigated. The results show that the gas sensor based on multi-layered SnO2 nanoarchitectures exhibits higher sensitivities compared with those of the single-layered ones. However, the response and recovery times are longer than the later one, indicating a lower diffusion speed during the surface contact reactions. The mechanism for the different gas-sensing performance of single- and multi-layered SnO2 nanomaterials was further demonstrated from the kinetic processes of gas adsorption/desorption. Our findings shed a light for the design of novel nanoparticle-assembled architectures for applications based on surface contact reactions such as security monitoring and environmental sensors.