Synthesis and highly enhanced acetylene sensing properties of Au nanoparticle-decorated hexagonal ZnO nanorings

Hexagonal ZnO nanorings were synthesized using a one-step hydrothermal method and Au nanoparticles were decorated on the surface of the ZnO nanorings through a facile deposition process. The as-prepared ZnO nanorings showed a well-defined hexagonal shape with a width of 0.75-1.4 mu m, a thickness of 0.17-0.33 mu m and a hollow size of 0.2-1 mu m. For the Au nanoparticle-decorated hexagonal ZnO nanorings (Au-ZnO nanorings), Au nanoparticles with a size of 3-10 nm were distributed discretely on the surface of the ZnO nanorings. The acetylene sensing performance was tested for the ZnO nanorings and Au-ZnO nanorings. The results indicated that the Au-ZnO nanorings showed a higher response (28 to 100 ppm acetylene), lower operating temperature (255 degrees C), faster response/recovery speed (less than 9 s and 5 s, respectively), and lower minimum detectable acetylene concentration (about 1 ppm). In addition, the mechanism for the enhanced acetylene-sensing performance of the Au-ZnO nanorings was discussed.