Preparation of camphor-sulfonic acid doped PPy-NiO hybrid nanocomposite for detection of toxic nitrogen dioxide

Present study explores detection limit enhancement of toxic nitrogen dioxide (NO₂) gas using camphor sulfonic acid (CSA)-doped PPy-NiO hybrid material sensor at room temperature. The morphology and structure of as-prepared samples are confirmed from the field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction pattern, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy techniques. The NO₂ gas sensing properties of CSA-doped PPy-NiO hybrid nanocomposite are compared with the pure PPy and PPy-NiO gas sensors. Gas sensor designed for 30% CSA-doped PPy-NiO hybrid nanocomposite sample demonstrated considerable sensing performance to a dilute level of NO₂ gas. The response of the CSA-doped PPy-NiO hybrid sensor to 100 ppm NO₂ is nearly twice compared to pure PPy. The response and recovery times are reduced significantly compared to the PPy and PPy-NiO sensors. Enhancement of gas sensing properties are assigned to change of the morphology and activity of CSA with PPy and NiO as well as their hybrid interfaces in the optimum gas sensors; confirmed by series of as well-performed experiments. The plausible sensing mechanism of CSA-doped PPy-NiO hybrid nanocomposite is also proposed.