Synthesis of NiO-decorated ZnO porous nanosheets with improved CH4 sensing performance

Aimed at improving the methane (CH₄) sensing performance, this paper presents the preparation of pure and NiO decorated ZnO porous nanosheets (PNSs, with the size of 200 nm) through a hydrothermal route combined with post-treatment, in which the pre-prepared Zn₅(CO)₃(OH)₆ was employed as sacrificial template. The specific surface areas of ZnO decorated with NiO nanoparticles is higher than that of pure ZnO. The introduction of NiO on ZnO PNSs not only increases the specific surface areas of ZnO/NiO PNSs, but also could promote the formation of p-n heterojunction at the interface of NiO and ZnO. The sensing results indicate that the sensor based on NiO-decorated ZnO PNSs exhibit an enhanced sensing performance in the comparison with pure ZnO PNSs at the working temperature of 340 °C, such as higher response and good long-term stability within 30 days, as well as the capacity of response-recovery. These results demonstrate that the potential application for CH₄ detection of ZnO/NiO PNSs. Besides, the improved sensing mechanism of ZnO/NiO was also discussed in the paper.