Enhanced Room-temperature Ammonia Sensing Performance of PANI@ZnO/Fe₃O₄Hybrid Nanocomposites Synthesized via Chemical Oxidative Polymerization
J. Environ. Nanotechnol., Volume 15, No 3 (September 2026) pp. 851-868
Abstract
Hybrid organic–inorganic nanocomposites have attracted considerable attention owing to their enhanced sensitivity toward oxidizing and reducing gases and their potential for sustainable sensing technologies. In this study, a novel PANI@ZnO/Fe₃O₄ hybrid nanocomposite film was synthesized through chemical oxidative polymerization for high-performance ammonia sensing under ambient conditions. The incorporation of ZnO and Fe₃O₄ nanoparticles into the PANI matrix resulted in measurable changes in the structural, optical, and thermal characteristics of the hybrid nanocomposite. The successful formation of the hybrid nanocomposite was confirmed through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, and thermogravimetric analysis (TGA). The optical band gap decreased from 3.18 eV for pure PANI to 2.79 eV for the PANI@ZnO/Fe₃O₄-5 nanocomposite, indicating improved charge transfer characteristics. Among the fabricated sensors, the PANI@ZnO/Fe₃O₄-5 sensor exhibited the highest sensing response of approximately 215% toward 300 ppm NH₃, with a sensitivity of 0.727 % ppm⁻¹ (R² = 0.9989) over the investigated concentration range of 50–300 ppm and rapid response and recovery times of about 11 s. The sensor also demonstrated excellent selectivity against interfering gases, including CO, CO₂, H₂S, and ethanol, together with good long-term stability and humidity tolerance. The enhanced sensing performance may be associated with interactions among PANI, ZnO, and Fe₃O₄ nanoparticles and the resulting changes in the sensing behavior toward NH₃. These findings demonstrate the potential of PANI@ZnO/Fe₃O₄ hybrid nanocomposites as sustainable materials for advanced environmental monitoring and room-temperature ammonia sensing applications.
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Reference
Al-Gharram, M. and AlZoubi, T., Exploring dual optical responses of Polyaniline-Fe2O3 nanocomposites for advanced optoelectronic and supercapacitor applications, Ceram. Int., 51(18), 24916–24934 (2025).
https://doi.org/10.1016/j.ceramint.2025.03.173
Al-Gharram, M., Uhlmann, P. and Al-Hussein, M., Highly dispersed crystalline magnetic and conductive polyaniline/iron oxide nanocomposite films, Colloids Surf. A: Physicochem. Eng. Aspects, 684, 133212 (2024).
https://doi.org/10.1016/j.colsurfa.2024.133212
Andre, R. S., Dos Santos, D. M., Mercante, L. A., Facure, M. H. M., Campana-Filho, S. P., Mattoso, L. H. C. and Correa, D. S., Nanochitin-based composite films as a disposable ethanol sensor, J. Environ. Chem. Eng., 8(5), 104163 (2020).
https://doi.org/10.1016/j.jece.2020.104163
Basha, B., Aldhafeeri, T. R., Tariq, R., Akhtar, M., Alsaiari, N. S., Al-Buriahi, M. S., Warsi, M. F. and Zulfiqar, S., Carbonaceous glass electrode fabricated with L-cysteine incorporated C@Fe2O3 for the ultra-selective determination of toxic metal ions, J. Water Process Eng., 75, 107897 (2025).
https://doi.org/10.1016/j.jwpe.2025.107897
Bilgic, A. and Cimen, A., A highly sensitive and selective ON-OFF fluorescent sensor based on functionalized magnetite nanoparticles for detection of Cr(VI) metal ions in the aqueous medium, J. Mol. Liq., 312, 113398 (2020).
https://doi.org/10.1016/j.molliq.2020.113398
Buledi, J. A., Shaikh, H., Solangi, A. R., Mallah, A., Shah, Z. U. H., Khan, M. M., Sanati, A. L., Karimi-Maleh, H., Karaman, C., Camarada, M. B. and Niculina, D. E., Synthesis of NiO-Doped ZnO Nanoparticle-Decorated Reduced Graphene Oxide Nanohybrid for Highly Sensitive and Selective Electrochemical Sensing of Bisphenol A in Aqueous Samples, Indus. Eng. Chem. Res., 62(11), 4754–4764 (2023).
https://doi.org/10.1021/acs.iecr.2c04091
Daramola, O. B., Torimiro, N., George, R. C., Daramola, I. V and Omole, R. K., Affinity Capture Using Ligand and Polymer-Functionalized Iron Oxide, Gold and Iron-Gold Nanocomposites to Target Enteric Bacteria, BioNanoSci., 15(1), 8 (2025).
https://doi.org/10.1007/s12668-024-01682-9
Manasa, G., Mascarenhas, R. J. and Basavaraja, B. M., Sensitively-selective determination of Propyl Paraben preservative based on synergistic effects of polyaniline-zinc-oxide nano-composite incorporated into graphite paste electrode, Colloids Surf. B: Biointerf., 184, 110529 (2019).
https://doi.org/10.1016/j.colsurfb.2019.110529
Ghaffarirad, M. A., Sabahi, A., Golshani, Z., Manteghi, F. and Ghaffarinejad, A., Non-enzymatic glucose electrochemical sensor based on nitrogen-doped graphene modified with polyaniline and Fe3O4@MIL-101-NH2 nano framework, Inorg. Chem. Commun., 159, 111812 (2024).
https://doi.org/10.1016/j.inoche.2023.111812
Gunasekaran, Y., Suntharam, N. M., Bashir, S., Vengadaesvaran, B., Gunasegeran, S., Gopalakrishnan, N., Ramesh, S., Ramesh, K., Gerard, O. and Pershaanaa, M., Synthesis and characterization of ZnO/biochar composite as electrode material for hybrid supercapacitor, Ionics, 32(2), 1987-2010 (2025).
https://doi.org/10.1007/s11581-025-06839-4
Handore, K. N., Sharma, S. B. and Chabukswar, V. V., One-pot ultrasound synthesis of polyaniline–ZnO and its synergistic effect on microbial activity, RSC Adv., 15(45), 37856–37864 (2025).
https://doi.org/10.1039/d5ra04461h
Hasan, I. M. A., Tawfik, A. R. and Assaf, F. H., Green Iron Oxide Nanoparticles as a Modifier of Carbon Paste Electrode for Electrochemical Estimation of Paracetamol in Pharmaceutical Samples, Russian J. Electrochem., 57(5), 435–447 (2021).
https://doi.org/10.1134/s1023193521050050
Kyomuhimbo, H. D., Feleni, U., Haneklaus, N. H. and Brink, H. G., ZnO–Polyaniline Nanocomposite Functionalised with Laccase Enzymes for Electrochemical Detection of Cetyltrimethylammonuium Bromide (CTAB), J. Xenobio., 14(4), 1988–2002 (2024).
https://doi.org/10.3390/jox14040106
Liu, X., Gao, T., Liu, H., Fang, Y. and Wang, L., Fabrication of peroxidase-mimic iron oxide/carbon nanocomposite for highly sensitive colorimetric detection, J. Exp. Nanosci., 17(1), 75–85 (2022).
https://doi.org/10.1080/17458080.2022.2030470
Mahmood, W. K., Rashid, T. M., Rahmah, M. I., Jasim, A. M., Fahem, M. Q., Jabir, M. S., Abid, D. A., Majed, R. A., Awaid, D. M. and Yosif, H. M., Empowering NO2 Detection: Synthesis of Highly Responsive Au/Cu-Doped Iron Oxide Nanoparticles as Gas Sensors Through Laser Ablation, Plasmonics, 19(6), 3167–3176 (2024).
https://doi.org/10.1007/s11468-024-02235-2
Murugan, S., Srinivasan, G., Kotteeswaran, S., Jeyaraj, W., Govindasamy, M. and Thangavel, K., Green synthesis of Ag2O/ZnO nanocomposite for efficient antibacterial property and tunable electrochemical detection of hydrogen peroxide, J. Environ. Chem. Eng., 13(3), 116394 (2025).
https://doi.org/10.1016/j.jece.2025.116394
Murugesan, K., Das, S. and Dutta, K., Application of polyaniline/zinc oxide nanocomposites for non-enzymatic cholesterol detection: A preliminary investigation on the effect of dopants on the morphology, thermal stability, electrochemical and sensing behavior of the nanocomposites, Polym. Plast. Technol. Mater., 63(10), 1239–1253 (2024).
https://doi.org/10.1080/25740881.2024.2326144
Mutlaq, S., Albiss, B., Al-Nabulsi, A. A., Jaradat, Z. W., Olaimat, A. N., Khalifeh, M. S., Osaili, T., Ayyash, M. M. and Holley, R. A., Conductometric immunosensor for escherichia coli o157:H7 detection based on polyaniline/zinc oxide (pani/zno) nanocomposite, Polym., 13(19), 3288 (2021).
https://doi.org/10.3390/polym13193288
Niaz, A., Arain, M. B. and Soylak, M., Simultaneous voltammetric determination of dopamine and uric acid using screen printed carbon electrode modified with quercetin functionalized-iron oxide nanoparticles, Mater. Res. Bull., 185, 113317 (2025).
https://doi.org/10.1016/j.materresbull.2025.113317
Pakapongpan, S., Poo-arporn, Y., Tuantranont, A. and Poo-arporn, R. P., A facile one-pot synthesis of magnetic iron oxide nanoparticles embed N-doped graphene modified magnetic screen printed electrode for electrochemical sensing of chloramphenicol and diethylstilbestrol, Talanta, 241, 123184 (2022).
https://doi.org/10.1016/j.talanta.2021.123184
Pandey, A., Saini, S. K., Singh, R. K. and Mohanty, T., Power dependent tunable optical nonlinearity in Iron oxide/Borophene core-shell nanoparticles under ultrashort laser excitation, Optics Laser Technol., 181, 111761 (2025).
https://doi.org/10.1016/j.optlastec.2024.111761
Rajyashree, L., Manoharan, C., Loganathan, A. and Venkateshwarlu, M., Electrochemical and sensing properties of α-Fe2O3 nanoparticles synthesized using hydrothermal method at low reaction temperature, J. Mater. Sci. Mater. Electron., 34(6), 462 (2023).
https://doi.org/10.1007/s10854-023-09822-9
Shanavash, A., Sri, T. S., Mayakannan, S., Shanmugam, S. K., Chandankhede, P. H. and Sivakumar, B. G., Development of a carbon–perovskite self-powered IoT sensor node with dual-mode sensing, Interact., 247(1), 175 (2026).
https://doi.org/10.1007/s10751-026-02516-8
Singh, V. P., Singh, C. P., Kumar, S., Pandey, S. K. and Punetha, D., Microwave-Assisted Synthesis and Characterization of Iron Oxide Nanoparticles for Advanced Biomedical Sensing Applications, IEEE Open J. Nanotechnol., 6, 10–15 (2025).
https://doi.org/10.1109/OJNANO.2024.3514866
Tamilarasi, K., Jayasurrya, M., Meena, M., Vimalan, M. and Vetha, P. I., Novel PANI–Pb3O4 composites with enhanced electrochemical properties for supercapacitor application, J. Mater. Sci. Mater. Electron., 37(14), 1038 (2026).
https://doi.org/10.1007/s10854-026-17397-4
Toderascu, L. I., Sima, L. E., Orobeti, S., Florian, P. E., Icriverzi, M., Maraloiu, V.-A., Comanescu, C., Iacob, N., Kuncser, V., Antohe, I., Popescu-Pelin, G., Stanciu, G., Ionita, P., Mihailescu, C. N. and Socol, G., Synthesis and Anti-Melanoma Activity of L-Cysteine-Coated Iron Oxide Nanoparticles Loaded with Doxorubicin, Nanomater., 13(4), 621 (2023).
https://doi.org/10.3390/nano13040621
Tümay, S. O., Şanko, V., Şenocak, A. and Demirbas, E., A hybrid nanosensor based on novel fluorescent iron oxide nanoparticles for highly selective determination of Hg2+ions in environmental samples, New J. Chem., 45(32), 14495–14507 (2021).
https://doi.org/10.1039/d1nj02908h
Ullah, N., Ali Shah, A. U. H., Jan, F. A., Ansir, R. and Muhammad, W., Application of modified PANI-ZnO composites for NH3Gas sensor at ambient temperature, J. Chem. Soc. Pakistan, 42(3), 390–398 (2020).
Velayudham, R. and Natarajan, J., Multifunctional application of different iron oxide nanoparticles, Zeitschrift Fur Physikalische Chemie, 239(2–3), 379–395 (2025).
https://doi.org/10.1515/zpch-2024-0745
Yan, S., Shen, D., Xin, B., Newton, M. A. A. and Wu, Y., Rhombus-patterned flexible self-supported PVDF-based humidity sensor for respiratory monitoring, Polym., 282, 126139 (2023).
https://doi.org/10.1016/j.polymer.2023.126139
Yang, J., Du, M., Wu, W., Chen, Q., Niu, J. and Zhang, Z., Polyaniline-modified iron oxide nanoparticles to improve the overall performance of MFC-BOD sensors, J. Water Process Eng., 71, 107189 (2025).
https://doi.org/10.1016/j.jwpe.2025.107189
Yang, Q., Li, N., Li, Q., Chen, S., Wang, H. L. and Yang, H., Amperometric sarcosine biosensor based on hollow magnetic Pt–Fe3O4@C nanospheres, Anal. Chimica Acta, 1078, 161–167 (2019).
https://doi.org/10.1016/j.aca.2019.06.031
Yang, Z., Liu, Q., Zhang, L., Dai, J. and Shen, Z., Green one-pot synthesis of binder-free porous edge-functionalized graphitic carbon nitride/iron oxide nanoparticles nanocomposite as an outstanding electrode for supercapacitors, J. Energy Storage, 32, 101909 (2020).
https://doi.org/10.1016/j.est.2020.101909
Yıldız, D. E., Unal, F. and Taşaltın, N., Non-enzymatic electrochemical voltammetric sensors based on thulium:zinc oxide for dopamine detection, J. Mater. Sci. Mater. Electron., 35(7), 475 (2024).
