Rational design of ZnO-SnO2 Janus nanofibers for highly sensitive triethylamine detection

Herein, ZnO-SnO₂ Janus nanofibers (NFs) were synthesized by a parallel electrospinning method and its sensing performances were tested. Considering the compositions of the two metal oxide semiconductors in Janus structure, different ratios of ZnO and SnO₂ were designed and controlled. The optimum ratios of ZnO and SnO₂ was 1:2 by analyzing their sensing performances to triethylamine (TEA) gas. Gas sensors based on ZS-12 Janus NFs exhibited a high response to TEA (45.2) and an excellent sensing response/recovery reproducibility. In order to investigate the sensing mechanism of Janus structure, ZnO NFs and SnO₂ NFs were synthesized and used as controlled experiment. The results indicated that the heterostructures in Janus NFs is the key factor for the enhanced TEA sensing performances. The electrons flowed in the ZnO-SnO₂ Janus structure leading to the variation of ionic oxygen species and electron depletion layer. These phenomena improved the reaction of TEA gas molecules with ionic oxygen species so that the TEA sensing performances were enhanced. Based on the Janus structures, a satisfactory gas sensor for detecting TEA gas were developed. Significantly, this work investigated the sensing mechanism of Janus structures and provided an efficient strategy for the gas sensing materials.