Porous rod-like Co(OH)F/Co3O4 heterojunction-based acetic anhydride gas sensor with high response and low operating temperature

In response to the pressing demand for acetic anhydride gas detection, this study introduces a novel gas sensor for precisely detecting acetic anhydride concentrations. The optimum conditions for the synthesis of cobalt hydroxyfluoride/cobalt oxide (CHFCO) heterojunctions with good acetic anhydride gas sensitivity were deter-mined by carefully adjusting the calcination time, hydrothermal time and ammonium fluoride content. The best performing composite CHFCO sensor with porous rod particles was tested at 180 celcius and achieved a response rate of 260 for 100 ppm acetic anhydride gas, with response and recovery times of 60 and 40 s, respectively. In comparison to other prepared sensors, the detection response for acetic anhydride was improved by a factor of 4.30-23.63. Moreover, the CHFCO sensor reliably detected acetic anhydride at a concentration of 500 ppb, exhibiting a response value of 1.56. Notably, the sensor demonstrated great selectivity, moisture resistance, and stability. The findings highlight the significant enhancements in gas-sensitive performance to acetic anhydride achieved by the abundant hydroxyl bonds on the surface of CHFCO heterojunction, the presence of fluorine ions, and the modulation of the band gap. These results provide valuable insights for the advancement of acetic an-hydride gas sensors based on CHFCO heterojunction.