Highly sensitive NO2 gas sensor based on Au-decorated MoS2 nanosheets/ SnO2 nanowires heterostructures with self-heating capability

초록

NO2 is a toxic gas that contributes to environmental pollution and presents serious health risks. To reliably detect this hazardous gas, we developed a highly selective and sensitive NO2 gas sensor. First, SnO2 nanowires (NWs) were grown via a vapor-liquid-solid (VLS) process and then combined with MoS2 nanosheets (NSs). Next, Au nanoparticles (NPs) were decorated onto the composite through a reduction process. Characterization results confirmed the successful synthesis of a crystalline nanocomposite with NW/NS morphologies and uniformly distributed Au NPs on the surface. At 75 degrees C, the Au-decorated sensor produced a response of 26-1 ppm NO2, while the response without Au decoration was nearly halved at the optimal sensing temperature of 100 degrees C. Additionally, under self-heating operation, the Au-decorated sensor showed its maximum response at an applied voltage of 3 V and could detect NO2 concentrations as low as 250 ppb. The improved sensing performance was due to the catalytic activity of Au NPs, the formation of Schottky junctions between Au and both SnO2 and MoS2, and the formation of heterojunctions between SnO2 and MoS2. Furthermore, the high surface area created by the combination of NWs and NSs provides numerous adsorption sites for gas molecules on the sensor surface.

키워드