High performance methyl salicylate gas sensor based on noble metal (Au, Pt) decorated WO3 nanofibers

Methyl salicylate (MeSa) is known as a volatile plant pathogen biomarker and a chemical warfare agent simulant. Herein, high performance MeSa gas sensors were developed by optimizing morphology and composition of noble metal decorated tungsten trioxide (WO3) nanofibers. Using optimized nanofibers, 100 ppb of MeSa were readily sensed in dry air whereas the calculated low limit of detection (LLOD) is expected to be in a few tens of ppb. Pt-WO3 (1.1 at% Pt) nanofibers also show an excellent selectivity over other volatile organic compounds including aromatic compounds (i.e., benzene, toluene, ethyl benzene, p-xylene). Systematic characterization of sensors in environments with different oxygen contents indicated that surface carrier concentration significantly altered as a function of Au and Pt content. Although 1.7 at% Au-WO3 nanofibers based sensor has higher sensing response toward MeSa, 1.1 at% Pt-WO3 nanofibers were found to be a more promising sensing material for MeSa detection because of higher selectivity over other VOCs and lower calculated LLOD ( similar to 41 ppb).