Engineering of Au nanoparticles over hollow MoS2/C nanoreactor for enhanced TEA sensing at low temperature

Surface modification with noble metal is an effective strategy to improve gas sensitive properties of semiconductive materials. Herein, hollow MoS2/C nanoreactors assembled with nanosheets were synthesized with the incorporation of water-oil two-phase microemulsion method and following heating treatment. Through adjusting the polarity of hydrothermal reaction solvent, Au nanoparticles (NPs) of different size were loaded on MoS2/C nanoreactors, whose average size could be efficiently tailored from 5.73 to 42.6 nm. The results of gas sensing measurement show that Au modification can remarkably increase triethylamine (TEA) sensing properties of MoS2/C–based sensor at lower temperature. Especially, for Au@MoS2/C-2 with Au NPs size of about 9.9 nm, the response value to 50 ppm TEA at 160 °C is high up to 240.5, which is 20 times higher than that of MoS2/C, and the response-recovery times are highly reduced from 80 s/500 s–13 s/198 s. Besides, Au@MoS2/C-2 sensitive element has excellent selectivity, humidity resistance, and long-term stability for TEA. This enhancement in TEA response is properly attributed to the modified interfacial interaction between Au NPs and MoS2/C, which leads to the formation of Schottky contact and boosts the charge transfer. So, hollow Au@MoS2/C nanoreactors will be a potential candidate for TEA detection. •A group of hollow Au@MoS2/C nanoreactors were synthesized.•The sizes of Au NPs were tailored by adjusting the polarity of reaction solvent.•Au@MoS2/C-2 sensor exhibited the best sensing performance to TEA at low temperature.•The enhanced gas sensing mechanism for TEA was revealed by DFT results.