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 μm, a thickness of 0.17–0.33 μm and a hollow size of 0.2–1 μm. 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 °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.