MoS 2 nanochains were successfully prepared via facile electrospinning and a hydrothermal process. The morphology of MoS 2 nanochains was evaluated by field emission scanning electron microscopy and high-resolution transmission electron microscopy. A slurry composed of the MoS 2 nanochains was coated on a silver electrode to detect ammonia. The detection range of ammonia was between 25 and 500 ppm. MoS 2 nanochains offered outstanding sensing response, repeatable reproducibility, and excellent selectivity with a detection limit of 720 ppb. The responsiveness of MoS 2 nanochains to ammonia remained unchanged for 1 week.

In this work, a selective and highly sensitive gas sensor using tungsten oxide (WO 3 ) nanofibers was fabricated via electrospinning. WO 3 was functionalized with gold nanoparticles by magnetron sputtering at different sputtering times to obtain Au films with thicknesses of 1, 5, 10, and 15 nm. The sensing performance of Au film composite nanomaterials with different Au layer thicknesses was tested at 100−250 °C and different nitrogen dioxide (NO 2 ) concentrations ranging from 200 to 1000 ppb. The findings showed that the 10 nm Au−WO 3 composite nanomaterial sensor had the most significant improvement in the performance of the pristine WO 3 sensor compared with other Au−WO 3 composite nanomaterial sensors, and the optimal operating temperature of the sensor was 175 °C. The composite nanomaterial sensor exhibited excellent selectivity when exposed to different gases and also exhibited high sensibility when exposed to low concentrations of NO 2 under high humidity (80%). The mechanism of gas sensor performance improvement was also investigated.

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