Ag/Cu doped polyaniline hybrid nanocomposite-based novel gas sensor for enhanced ammonia gas sensing performance at room temperature

Abstract

Hybrid nanocomposites, which comprise organic and inorganic materials, have gained increasing attention in applications for enhanced sensing response to both reducing and oxidation gases. In this study, a novel nanocomposite is synthesized using chemical polymerization by reinforcing Ag/Cu nanoparticles with different concentrations doped into the polyaniline matrix. This hybrid nanocomposite is used as a sensing platform for ammonia detection with different concentrations (ppm). The homogeneous distribution of Ag/Cu nanoparticles onto the PANI matrix provides a smooth and dense surface area, further accelerating the transmission of electrons. The synergistic effect of the PANI@Ag/Cu matrix is responsible for the outstanding conductivity, compatibility, and catalytic ability of the proposed gas sensor. The structure, morphology, and surface composition of as-synthesized samples were examined using X-ray diffraction, field emission scanning electron microscopy, ultraviolet-visible spectroscopy, energy dispersive spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The results indicated that the resistive sensor based on the PANI@Ag/Cu₃ hybrid nanocomposite exhibited the highest response toward ammonia at room temperature, with a response value of 86% to a concentration of 300 ppm. We also investigated the sensing properties of volatile organic compounds, including carbon dioxide, carbon monoxide, ethanol and hydrogen sulphide. Characterization and gas sensing measurements exhibited protonation and deprotonation of the PANI@Ag/Cu heterojunction, which contributes to the ammonia sensing mechanism. Overall, the obtained findings demonstrated that the PANI@Ag/Cu hybrid nanocomposite is a promising material for gas sensing applications in environmental monitoring.