Hydrothermally synthesized ZnO hierarchical structure for lower concentration methane sensing

•The hierarchical structure ZnO was synthesized by one-step hydrothermal method.•The response of the sensor has a good linear with the lower concentration of CH4.•Hierarchical ZnO sensor has a low initial CH4 response concentration (10 ppm).•Hierarchical ZnO sensor has good stability.•The gas sensing mechanism of the hierarchical ZnO sensor for CH4 is discussed. Hierarchical microstructure ZnO was successfully prepared by a simple one-step hydrothermal method and annealing process, and its crystal structure, morphology and pore distribution were characterized. The gas sensing performance test results show that the response of the ZnO sensor has a good linear relationship with 10–500 ppm of methane, and the sensor has a low initial methane response concentration with good sensitivity and stability. This work implies that this hierarchical ZnO is expected to be a potential candidate for low-concentration methane sensing.