Au-Decorated 1D SnO2 Nanowire/2D WS2 Nanosheet Composite for CO Gas Sensing at Room Temperature in Self-Heating Mode

We have designed a new ternary structure to enhance the sensing properties of WS2 nanosheet (NS)-based gas sensors at room temperature (RT) in self-heating mode. SnO2 nanowires (NWs, 10-30 wt%) were added to WS2 NSs and then Au nanoparticles (NPs) were deposited on the surface of the resulting composites by UV irradiation. The Au-decorated 10 wt% SnO2-WS2 composition showed the highest gas sensing properties. The presence of SnO2 NWs on the WS2 NSs effectively enhanced the diffusion and adsorption of gas species into deeper parts of the gas sensor. Furthermore, the chemical sensitization of Au (increase in oxygen ionosorption; spillover effect and catalytic effect towards CO) contributed to an enhanced response to CO gas. Gas sensing tests performed in the self-heating mode demonstrated the possibility of realizing a low-voltage, low-power-consumption CO gas sensor based on the Au-decorated 10 wt% SnO2-WS2. The sensor response under 60% relative humidity (RH) conditions was 84% of that under dry conditions, which shows that CO sensing is possible in wet environments at room temperature operation.

Automated summary

A new ternary structure was designed to enhance the sensing properties of WS2 nanosheet-based gas sensors at room temperature in self-heating mode. SnO2 nanowires were added to WS2 nanosheets and Au nanoparticles were deposited on the surface of the resulting composites. The presence of SnO2 nanowires effectively enhanced the diffusion and adsorption of gas species, while the chemical sensitization of Au contributed to an enhanced response to CO gas. The results showed the potential of the Au-decorated SnO2-WS2 as a low-power, low-voltage CO gas sensor in wet environments.