Insight into highly selective dimethyl trisulfide detection based on WO3 nanorod bundles with exposed (002) facets

Metal oxide semiconductors (MOS)-based gas sensor for food-borne pathogens detecting via special biological metabolites, require high selectivity due to the possible sensing interference, which is an issue still to be resolved [1-4]. In this work, WO3 nanorod bundles were synthesized via a hydrothermal method, and its rapid response, high sensitivity and selectivity are demonstrated for detecting dimethyl trisulfide (DMTS), the biomarker of Listeria monocytogenes. The WO3-based sensor with high selectivity exhibited rapid response (10 s) and high response (94) behavior towards 10 ppm DMTS. The in situ Raman spectrum measurement results suggest that the excellent sensing behavior can be ascribed to the strong interaction between S atoms in DMTS and W sites on the (002) surface of WO3. Moreover, Density Functional Theory (DFT) calculation results also prove that the DMTS molecule exhibits the largest adsorption energy of 3.39 eV by S at W sites. The cleavage of S-SS- bonds through a catalytic behavior on W sites, which greatly enhances the reaction of the O- with DMTS, is suggested to be the mechanism of the WO3 sensor for detecting DMTS, which is in contrast to the sensing mechanism based on the traditional oxygen depletion theory.