Development of nanostructured polyaniline–titanium dioxide gas sensors for ammonia recognition

Abstract

The performance at room temperature of nanostructured polyaniline (PANi)-titanium dioxide (TiO 2 ) ammonia gas sensors was investigated. The PANi-TiO 2 thin-film sensors were fabricated with a spin-coating method on glass substrates. PANi-TiO 2 (0-50%) sensor films were characterized for their structural, morphological, optical, and various gas-sensing properties. The structural analysis showed the formation of nanocrystalline TiO 2 , whereas PANi exhibited an amorphous nature. Morphological analysis of the PANi-TiO 2 nanocomposites film revealed a uniform distribution of TiO 2 nanoparticles in the PANi matrix. The absorption peaks in the Fourier transform infrared spectra and ultraviolet-visible spectra of the PANi-TiO 2 composite film were found to shift to higher wave numbers compared to those observed in pure PANi. The observed shifts were attributed to the interaction between the TiO 2 particles and the PANi molecular chains. The gas-sensing properties showed that the sensors exhibited selectivity to ammonia (NH 3 ) at room temperature.

Chemiresistive polyaniline-based gas sensors: A mini review

“…A hybrid material particularly suitable for NH 3 recognition based on nanostructured polyaniline and titanium dioxide [PANi-TiO 2 ] has been recently proposed and characterized by morphological analysis by Pawar et al [57]. The response at room temperature of different oxiding and reducing gases of PANi-TiO 2 film is shown in Fig.…”

Surface acoustic wave ammonia sensor based on ZnO/SiO2 composite film

“…exhibited good sensitivity with the detection level up to 6 ppm, but the response time is up to 10 min, moreover, the sensor didn't show a good selectivity. Pawar et al [17] reported a nanostructured polyaniline-titanium dioxide gas sensor for ammonia recognition. The sensor showed a good selectivity to ammonia, but the detection level was as low as 20 ppm ammonia.…”

Ammonia gas sensors based on In2O3/PANI hetero-nanofibers operating at room temperature

“…A possible mechanism for the selectivity to NH 3 is the chemisorption of NH 3 on PANI in In 2 O 3 /PANI-2 forming ammonium [32]. Besides, the different gases show different electron affinity values [33], and the varying sensitivity of In 2 O 3 /PANI-2 nanofibers to different gases may be explained by this.…”