Ultraselective acetone-gas sensor based ZnO flowers functionalized by Au nanoparticle loading on certain facet

ZnO flowers with thin sheet and hemisphere shapes were fabricated via thermal decomposition in an organic solvent. Especially, typical hemisphere morphology with exposed (002) crystal face were created for the first time. Because of exposed (002) facet increased, a facet-like heterostructure of ZnO formed to get enhanced sensor performance, especially after loading Au nanoparticles (NPs) using a supersonic chemistry way. Gas sensing tests indicate that the hemisphere Au/ZnO sensor with the best performance and a nice selectivity to acetone. This is ascribed that the unique second-level structure provides more active centers and diffusion channels for acetone molecules. Au NPs increases the thickness of the surface electron depletion layer, which enhanced the sensitivity of the gas sensor.