Enhanced TEA sensing properties of nest-like ZnO by decoration with Au

Abstract

A nest-like ZnO morphology was successfully prepared by a reliable solvothermal route. The obtained nest-like ZnO nanostructure was about 200 nm in size and densely assembled with numerous nanoparticles (NPs) of about 8.6 nm in size. Through a simple impregnation method, different amounts of Au NPs were evenly decorated on the as-prepared ZnO nanostructure. It was found that after introduction of Au, the size of primary ZnO NPs in the nest-like structure increased from 8.6 nm to 43.2 nm, however, the sensor based on Au/ZnO composites still revealed strikingly enhanced TEA sensing properties at its optimum working temperature of 320 °C. The gas response value of the NZA-2 (molar ratio between Au and ZnO is 2:100) sensor towards 200 ppm TEA is as high as 625 (Ra/Rg), which is about 6 folds that of the pure ZnO sensor (97). More importantly, the NZA-2 sensor also showed good selectively, low detection limit (1ppm), fast response/recovery speed (200 ppm TEA, 4s/26s), and good repeatability and long-term stability. These sensing properties made the Au-decorated ZnO nest-like nanostructure a promising candidate for fabricating TEA sensor. The increased gas sensitivity of Au/ZnO was illustrated by the good catalytic properties of Au NPs.