Room Temperature Ammonia Gas Sensor Based on Polyaniline-TiO$_{2}$ Nanocomposite

Abstract

In the present work, we report on the performance of room temperature ammonia gas sensor based on polyaniline-titanium dioxide (PANi-TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) nanocomposite. The nanocomposite was fabricated using the spin coating method on glass substrates. PANi-TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (0%-50%) nanocomposite films were characterized for their structural as well as surface morphologies, UV-Vis and various gas responses were studied. The XRD analysis showed formation of nanocrystalline TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , while polyaniline exhibited amorphous nature. Morphological analysis using scanning electron microscopy of PANi-TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanocomposite film revealed uniform distribution of TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanoparticles in PANi matrix. The absorption peaks in FTIR and UV-Vis spectra of PANi-TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> composite film were found to shift to a higher wave number as compared to those observed in pure PANi. The observed shifts were attributed to the interaction between the TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> particle and PANi molecular chains. The gas sensing properties showed the sensor exhibit selectivity to ammonia (NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) at room temperature.