Interface engineering of highly sensitive and humidity independent PPy/SnO2 nanocomposites for room temperature ammonia gas detection

Abstract

Tin oxide (SnO₂) nanoparticles have been synthesized by Sol–Gel method. Polypyrrole (PPy)–tin oxide (SnO₂) hybrid nanocomposite has synthesized by chemical polymerization of PPy in the presence of SnO₂ nanoparticles. The band gap energy of the hybrid nanocomposite is calculated as 3.39 eV using UV–VIS absorption spectroscopy. The synthesized SnO₂ nanoparticle is tetragonal rutile structure which has been confirmed using X-ray diffraction spectroscopy. Scanning electron microscope is involved in the morphological analysis of the hybrid nanocomposite. Sensing electrodes are fabricated by spin coating of the sensing material on printed circuit board. The electrodes have been investigated for their sensing behaviour towards oxygen (O₂), hydrogen (H₂), ammonia (NH₃), carbon dioxide (CO₂) and liquid petroleum gas at room temperature. The fabricated electrode is selectively sensitive to 1 ppm of NH₃ with improved sensitivity (55%), response time (20 s) and recovery time (8 s). The electrode shows stable sensitivity towards NH₃ at different ranges of relative humidity (% RH) (30%, 50% and 80%). The electrode maintains 85.33% stability for the period of 50 days.