Highly dispersed Au nanoparticles decorated WO3 nanoplatelets: Laser-assisted synthesis and superior performance for detecting ethanol vapor.

Loading of noble metal nanoparticles (NPs) on the surfaces of semiconductor oxides to form a hybrid nanostructure is an effective strategy to improve gas-sensing performance. In this study, WO3 nanoplatelets decorated with Au NPs were prepared by laser ablation in liquids (LAL) with subsequent aging and annealing treatments. Results indicated that Au NPs with an average size of 7.8 ± 2.5 nm were highly dispersed on the surface of WO3 nanoplatelets. As gas-sensing materials, the obtained Au-decorated WO3 nanoplatelets showed lower operating temperature of 320 °C and higher response value of 3.5-fold in detecting ethanol molecules compared with pure WO3 nanoplatelets. Moreover, Au-decorated WO3 nanoplatelets displayed good selectivity toward ethanol compared with other tested vapors and excellent stability within several cycled measurements. These results can be ascribed to the supported Au NPs, which promote the adsorption and dissociation of oxygen species, eventually resulting in accelerated electron depletion on the surface of Au-WO3 hybrids.