Recently, the most approach by the combination of inorganic/organic materials to form hybrid structures has been attracted more attention in fields such as sensors, battery, LED, catalyst, etc. Gas sensors based on inorganic/organic hybrid structures were investigated in many research groups with aiming at finding materials for room temperature operation, high selectivity and sensitivity to target gases. On the other hand, the mechanism or formation of inorganic/organic hybrids still needs to be verified in more detail. In this paper, the authors conducted the fabrication of NiO/PPy hybrid nanostructured films by chemical vapor-phase polymerization when using NiO nanoparticles films drop-coated FeCl3 oxidant. The investigation results on X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy, Raman scattering spectroscopy and gas-sensing performance of the synthesized films proved the formation of a hybrid structure between inorganic (polypyrrole - PPy) and organic (nickel oxide nanoparticles - NiO). The NiO/PPy films presented having a very high sensitivity to NH3 gas was considered by the role of NiO/PPy hybrids. The highest sensitivity to NH3 gas with the sensing response S = 246.6% for 350 ppm at 25 oC was found for the NiO/PPy film with the used 0.2 M FeCl3 oxidant solution.
Figure 1: (a) SEM image of the NiO/PPy hybrid; (b) illustration of the hybrid contact for enhancing the gas-sensing perfomance; (c) resistances of the NiO/PPy films changing with NH3 concentration; (d) dependence of the gas-sensing response on NH3 concentration, and (e) the gas-sensing response with the different rates of NiO/PPy hybrids.
The team's research results were published in the SCIE journal: Sensors and Actuators B (IF = 7.46), Volume 340, 1 August 2021, 129986, “High NH3 sensing performance of NiO/PPy hybrid nanostructures”.
Link: https://doi.org/10.1016/j.snb.2021.129986.