High-Sensitivity and Room-Temperature Nitrous Oxide Sensor Using Au Nanoparticles-Decorated MoS2

Room-temperature (RT) detection of nitrous oxide (N2O) gas in the atmosphere is important for human health and mitigating greenhouse gas emissions. A 2-D transition metal dichalcogenide facilitates high specific surface area and abundant active sites for room-temperature detection of various gases. However, low sensitivity, slow response, and poor selectivity limit the room temperature gas sensing performance. Here, the development of room-temperature detection of N2O is demonstrated using 2D molybdenum disulfide (MoS2) nanoflakes decorated with gold nanoparticles (AuNPs). The high specific surface area and excellent physical and chemical properties of MoS2 facilitate abundant active sites for adsorbing N2O, while the electron-donating effect of AuNPs modulates the electronic structure of MoS2 that can help to realize high sensitivity even at low concentrations of N2O. A facile solvent exfoliation method is utilized for preparing 2-D MoS2 nanoflakes and then functionalized with AuNPs. The MoS2-AuNPs sensor shows a 58% enhancement in sensor response for N2O at room temperature compared to pristine MoS2 gas sensors due to the n-doping effect of AuNPs. Furthermore, the sensor can detect N2O levels as low as 0.5 ppm. Additionally, the incorporation of AuNPs on MoS2 nanoflakes improves the selectivity toward N2O against a variety of interfering gases, including ammonia, nitric oxide, ethylene, and carbon dioxide. The possible reason could be that the dominant chemisorption of N2O on AuNPs-decorated MoS2 is more prevalent than that of other gases. Besides the enhanced response and excellent selectivity, the sensor shows good repeatability with a low relative standard deviation of 0.2% and stability over 30 days. Thus, this sensor could be a potential candidate for high-performance and room-temperature N2O gas sensing applications.

Automated summary

This study demonstrates the room-temperature detection of N2O gas using 2D molybdenum disulfide nanoflakes decorated with gold nanoparticles. The combination of the electron-donating effect of AuNPs and the properties of MoS2 enables high sensitivity and excellent selectivity, with the ability to detect N2O levels as low as 0.5 ppm.