Ammonia sensing properties of polyaniline/α-Fe2O3 hybrid nanocomposites

•Novel method of fabrication of PAni–Fe2O3 hybrid sensor.•PAni–Fe2O3 hybrid sensor showed maximum sensitivity 50% to NH3.•PAni–Fe2O3 hybrid sensor operates at room temperature.•Sensing mechanism of PAni–Fe2O3 hybrid sensor demonstrated using an impedance spectroscopy.

Polyaniline (PAni) films modified by different loading of α-Fe2O3 nanoparticles have been formed by solid state synthesis method and investigated for various oxidizing and reducing gases. We demonstrates that α-Fe2O3 nanoparticles (50%): PAni hybrid nanocomposites films are highly selective to NH3 with high sensitivity (50 at 100 ppm), fast response time (29 s) and highly reproducible response curves. X-ray diffraction analysis, field emission scanning electron microscopy observations, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis revealed that the n-type α-Fe2O3 nanoparticle transfers the electrons to polyaniline forms into a incredibly reduced state. These observations in PAni/α-Fe2O3 hybrid nanocomposites is insensitive to interaction with other gases except ammonia. The sensing mechanism of PAni/α-Fe2O3 hybrid nanocomposites to NH3 was interpreted with the help of proposed energy band diagram. In-addition to this, the interaction mechanism between the NH3 and PAni/α-Fe2O3 hybrid nanocomposite was investigated by an impedance spectroscopy tool.

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