Mesoporous Au@ZnO flower-like nanostructure for enhanced formaldehyde sensing performance

Abstract

The Au@ZnO flower-like nanostructure was successfully prepared by the facile hydrothermal method, and its gas-sensing property was studied. The produced Au@ZnO nanostructure presented an average diameter size of 170 ± 17 nm, and displayed an embedding structure with Au nanoparticle (average diameter size of 32 ± 6 nm) inside and a mesoporous ZnO layer outside. Impressively, the Au@ZnO flower-like nanostructure exhibited high sensitivity and remarkable selectivity toward HCHO, when it was applied for gas sensor. Compared with bare ZnO nanoparticles, the response value of the Au@ZnO nanoparticles toward 100 ppm HCHO at 220 °C is more than five times higher (45.28 vs. 8.86). The detailed investigations revealed that the Au nanoparticles inside contributed to the formation of Schottky barrier, which enhanced the sensitivity toward HCHO.