Organic–Inorganic Hybrid Materials for Trace Detection of Formaldehyde at Room Temperature

Detection and monitoring of trace gas analytes have become essential with the rapid advancements in manufacturing technology. Despite progress in developing gas sensing materials, many still struggle to meet fundamental requirements such as adequate sensitivity and stability, particularly due to high operational temperatures. To address this limitation, this study evaluates polymer–metal oxide hybrid materials designed for trace gas detection at room temperature. Polyaniline (PANI) hybrids doped with 5 wt % of TiO 2, SnO 2, ZnO, and Co 3 O 4 were synthesized in situ and characterized using FTIR, SEM, TEM, and EDX to analyze their chemical structure, morphology, and dopant incorporation. Pristine PANI and its metal oxide-doped variants were exposed to formaldehyde, and their sensing performance was evaluated at room temperature. Among the tested materials, PANI with 5 wt % Co 3 O 4 exhibited relatively higher sensitivity toward formaldehyde, attributed to the modified morphology and enhanced interactions as a result of Co 3 O 4 incorporation in PANI. To further investigate the effect of dopant concentration, PANI composites with lower Co 3 O 4 loadings were also evaluated. These findings provide insight into optimizing polymer-based gas sensors for enhanced performance at ambient conditions.