Sensitization performance of MWCNTs for ZnO-based methane gas sensor

Methane (CH 4 ) is a colorless, odorless, flammable, and explosive gas, making real-time monitoring critical for industrial and public safety. Conventional ZnO-based sensors are hindered by their requirement for elevated operating temperatures (>300 ℃), which severely constrains their practical applicability. To overcome this limitation, MWCNTs/ZnO composites were synthesized via a facile one-step hydrothermal method to enhance CH 4 sensing performance at low operating temperatures. Materials characterization revealed that the MWCNTs/ZnO composite possesses a substantially enhanced specific surface area (114.01   m²/g), approximately 3.5-fold greater than that of pristine ZnO nanosheets. Gas sensing tests demonstrated that the MWCNTs/ZnO composite exhibits a response of 2.21 toward 1500 ppm CH 4 at 50 °C, which is approximately two-fold higher than that of pristine ZnO nanosheets. The developed sensor simultaneously demonstrates exceptional selectivity and favorable humidity resistance. This study provides a new approach for developing low-power, high-sensitivity methane gas sensors. The sensitization performance of MWCNTs for ZnO-based methane gas sensor can be attributed to the geometric and electronic sensitization, as well as abundant active sites.