The “screening behavior” of lithium: Boosting H2S selectivity of WO3 nanofibers

An ideal way to boost the selectivity of sensing materials is that improving the sensitivity of the target gas while suppressing that of other interfering ones. Here, the “screening behavior” of the Li doped WO3 nanofibers (Li/WO3 NFs) have been discovered in suppressing the response from interfering gases, while elevating the H2S sensing response. Beneficially, the H2S response of Li/WO3 NFs sensor prototype is three times (Ra / Rg = 64@10 ppm) as high as that of the pristine WO3 ones (Ra / Rg = 21@10 ppm) at ~75% relative humidity and 260 °C. Moreover, Li/WO3 NFs sensor prototype presents the detection limit as low as 100 ppb. Particularly, the Li/WO3 NFs sensors detect simulated halitosis breath, of which the accuracy is comparable with gas chromatography. Theoretically, the decrease of the responses of Li/WO3 NFs to interfering gases is ascribed to the enhancement of the adsorption of water molecules by Li dopant. While the improved response to H2S is attributed to stronger adsorption of H2S and WO3 and to the increased defect oxygen. The “screening behavior” of Li doped into WO3 NFs provides a new strategy that might improve the selectivity of other gas sensing. [Display omitted] •The “screening behavior” of lithium are initially discovered.•The “screening blehavior” of lithium in boosting H2S selectivity of WO3 nanofibers.•The gas chromatography testify the sensor’s accuracy in detecting simulated H2S.