The significant improvement for BTX (benzene, toluene and xylene) sensing performance based on Au-decorated hierarchical ZnO porous rose-like architectures

A novel hierarchical ZnO rose-like architecture assembled by porous nanosheets was synthesized through a facile hydrothermal method combined with calcination process and used to fabricate gas sensors. The gas sensing measurements showed that the samples exhibited superior individual BTX (benzene, toluene and xylene) sensing properties. By designing more tiny pores on hierarchical rose petal-like nanosheet surface, the specific surface area of the samples was further extended. Besides, highly dispersed Au nanoparticles were grown on the ZnO rose-like architectures to enhance the gas sensing performance via a precipitation manner. Transmission electron microscopy (TEM) analyses indicated the average grain size of these Au nanoparticles was about 3 nm. The gas sensing results showed that the responses of the Au-ZnO sensor to 20 ppm individual benzene, toluene and xylene were 16.25 46.43 and 76.47, which were 4.33, 4.47 and 6.51 times higher than those of the pure specimens. Besides, the optimal working temperature was also decreased from 302 °C to 206 °C. The Au-ZnO sensor also exhibited short response/recovery times, low-concentration detection capability and good stability. The schottky contact between Au and ZnO, catalytic activity of Au nanoparticles and the specific ZnO porous rose-like architectures could be three pivotal factors for the superior BTX sensing properties.