fig4

Figure 4. NO gas sensing performance and sensing mechanism of the EEG/Co₃(HITP)₂ hybrid. (A) Schematic illustration of the experimental equipment for gas sensing measurements; (B) Schematic illustration of the NO sensing mechanism based on adsorption-induced charge transfer at the EEG/Co₃(HITP)₂ interface; (C) Dynamic responses of the gas-sensing module to NO at the detection limit of 25 ppb and at stepwise concentrations from 0.1 to 1 ppm; (D) Response and recovery characteristics of the sensor upon exposure to NO; (E) Repeatability of the sensor response under periodic NO injection; (F) Gas sensing response of the sensor under different humidity conditions; (G) Selectivity of the gas module toward NO compared with other gases; (H) Gas sensing responses measured at different ambient temperatures. The error bars represent the standard deviation based on a sample size of three (n = 3). NO: Nitric oxide; EEG: electrochemically exfoliated graphene.