SnO₂/PANI and SnO₂/PEDOT:PSS Aerogels for Highly Sensitive and Selective NH₃ Sensors

Hybrid nanocomposites for gas sensing were manufactured by depositing aerogels of SnO2, SnO2/ Polyaniline (PANI), and SnO2/PEDOT:PSS, synthesized via the epoxy route, onto alumina substrates. Key properties of the nanocomposites, including resistive responses, response and recovery times, sensitivity, and selectivity, were investigated. The influence of the composition of the aerogels on gas detection, specifically for ethanol (CH3CH2OH), acetone (C3H6O), and ammonia (NH3), was evaluated. All three SnO2 aerogel-based nanocomposites exhibited high selectivity for ammonia detection, with hybrid aerogels detecting concentrations as low as 50 ppb at room temperature (RT). Notably, the SnO2/PANI-based sensor detected a minimum ammonia concentration of 2 ppb. The enhanced detection at extremely low concentrations can be attributed to the combined features of composition and specific surface area of the nanocomposites.