Green-synthesized Zinc–copper–cobalt Oxide Nanoparticles: Structural, Morphological, Optical and Electrochemical Characterization for Photocatalytic and Supercapacitor Applications
J. Environ. Nanotechnol., Volume 15, No 3 (September 2026) pp. 104-117
Abstract
This study presents green synthesis of Zinc-Copper-Cobalt Oxide (ZCCO) using tulsi leaf extract as natural reducing agent. Nanoparticles were characterized to evaluate morphological, optical, structural, photocatalytic, and electrochemical characteristics. Powder X-ray diffraction (PXRD) analysis confirmed formation of crystalline mixed-metal oxide phase, while microscopic investigations revealed uniformly distributed nanosized particles with a distinct surface morphology. UV–Visible diffuse reflectance studies demonstrated efficient light absorption characteristics, indicating the suitability of the material for photocatalytic applications. Photocatalytic activity of nanoparticles was examined by degradation of organic dye pollutants under ultraviolet irradiation. The synthesized material exhibited remarkable dye degradation efficiency, demonstrating its potential for wastewater treatment applications. Electrochemical properties were further analysed by galvanostatic charge–discharge measurements, cyclic voltammetry, and electrochemical spectroscopy at alkaline electrolyte. The ZCCO nanoparticles displayed enhanced charge-transfer behavior, strong redox activity, and promising energy-storage performance. These findings suggest that, tulsi-mediated zinc-copper-cobalt oxide nanoparticles can serve as an effective multifunctional material for environmental remediation and electrochemical energy-storage technologies, thereby promoting sustainability. Furthermore, galvanostatic charge–discharge analysis confirmed good capacitive characteristics and excellent electrochemical stability, highlighting their suitability for supercapacitor and advanced energy-storage applications.
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Adarshgowda, N., Naik, H. S. B., Vishnu, G., Manjunatha, K. G. and Hareeshanaik, S., Impact of green-synthesized Mg-doped Mn ferrite nanoparticles on light-driven degradation of dyes and their optoelectronic applications, New J. Chem., 48(29), 13155–13170(2024).
https://doi.org/10.1039/d4nj02377c
Allah, S. M., Aslam, M. K., Hameed, S., -ul-Haq, M. E., Hussain, S., Al-Marzouqi, A. H. and Xu, M., Hierarchical sea-urchin anchored on rGO sheets decorated with layered double hydroxide nanoflowers: A novel electrode for enhanced supercapacitor performance, J. Energy Storage, 172, 122965 (2026).
https://doi.org/10.1016/j.est.2026.122965
Ansari, Z., Kadam, S., Kasabe, S., Tripathi, J., Agale, P., Patange, S. and More, P., Optimized Mn doped ZnO@rGO nanocomposites: a breakthrough for advanced energy storage and PEC systems, Ionics, 31(8), 8151–8172 (2025).
https://doi.org/10.1007/s11581-025-06468-x
Arpitha, S. B., Kumara Swamy, B. E. and Shashikumara, J. K. An efficient electrochemical sensor based on ZnO/Co3O4 nanocomposite modified carbon paste electrode for the sensitive detection of hydroquinone and resorcinol, Inorg. Chem. Commun., 152, 110656 (2023).
https://doi.org/10.1016/j.inoche.2023.110656
Asha, S. C., Divakara, S. G., Mahesh, B., Ravikumar, C. R. and Murthy, H. C. A., Improved photocatalytic activity triggered by UV light, as well as electrochemical sensing characteristics of MgO nanoparticles, Int. J. Environ. Anal. Chem., 105(18), 6221–6240 (2025).
https://doi.org/10.1080/03067319.2024.2415528
Baitha, R., Das, A. K., Kumar, S. and Manash, A., Green vs. chemical cerium oxide nanoparticles (CeO2-NPs): Integrated assessment of synthesis pathways, structural properties, ferroelectric behavior, and biomedical applications, Solid State Commun., 409, 116309 (2026).
https://doi.org/10.1016/j.ssc.2025.116309
Gaikwad, P. G., Mahamuni, G. P., Naik, N., Kulkarni, S. B. and Hiremath, P., Substrate driven growth of quaternary CoNiCuZn oxide nanostructures via electrodeposition for enhanced supercapacitor applications, Discover Mater., 6(1), 13(2026).
https://doi.org/10.1007/s43939-025-00439-9
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
Jose, V., Jose, V., Kuruvilla, E., Arunkumar, M., Deepi, A. S., Srikesh, G. and Nesaraj, A. S., Facile chemical synthesis of mixed Zn-Co manganite based tetragonal spinels for energy storage and environmental remediation, Optik, 291, 171335(2023).
https://doi.org/10.1016/j.ijleo.2023.171335
Kavica, S., Rajesh, P., Velmani, V. and Parethe, G. T., Biological Synthesis of Cobalt Oxide Nanoparticles Using Ziziphus oenopolia Leaf Extract, J. Environ. Nanotechnol., 13(1), 85-91(2024).
https://doi.org/10.13074/jent.2024.03.241510
Khawale, V. R., Kumar, R., Satishkumar, P., Haldar, B., Deepa, B., Saminathan, R., Veeramanikandan, P., Packirisamy, A. S. B. and Selvaraju, M., Study on Electrochemical Stability and Charge Transfer Efficiency for the Development of High-Performance Supercapacitors Using Iron Oxide (Fe2O3) Nanorods, J. New Mater. Electrochem. Syst., 27(3), 163–171(2024).
https://doi.org/10.14447/jnmes.v27i3.a01
Kubendhiran, S., Chung, R. J., Kongvarhodom, C., Chen, H. M., Yougbaré, S., Saukani, M., Wu, Y. F. and Lin, L. Y., Fast Fabrication of High-Performance Supercapacitor Electrodes Based on Two-Dimensional Trimetallic Zinc Manganese Cobalt-Layered Double Hydroxide Nanosheets Derived from Metal-Organic Frameworks, ACS Appl. Energy Mater., 8(10), 6339–6352 (2025).
https://doi.org/10.1021/acsaem.5c00018
Kumari, T., Phogat, D. and Shukla, V., Exploring the multipotentiality of plant extracts for the green synthesis of iron nanoparticles: A study of adsorption capacity and dye degradation efficiency, Environ. Res., 229, 116025(2023).
https://doi.org/10.1016/j.envres.2023.116025
Maghool, S., Asgharinezhad, A. A., Molaei, Z., Larimi, A. and Gotbi, C., CeO2-modified bimetallic sulfides for efficient energy storage in supercapacitors: A comparative study of ZnCoS and CuCoS, Mater. Today Chem., 54, 103684(2026).
https://doi.org/10.1016/j.mtchem.2026.103684
Marchetti, D., Scaravonati, S., Anyfanti, G., Aversa, L., Verucchi, R., Riccò, M., Massera, C., Gemmi, M., Pontiroli, D. and Pedrini, A., A green and efficient strategy for fabricating supercapacitor electrodes using a mechanochemically synthesised Cu-HHTP MOF, J. Mater. Chem. A, 14(27), 17207–17217(2026).
https://doi.org/10.1039/d6ta00182c
Maskaric, K., Ammar, A. U., Nan, A., Radu, T., Rostas, A. M. and Terenti, N., Transition metal-complexed lactone-functionalized poly(benzofuran-co-arylacetic acid) for enhanced supercapacitor efficiency, J. Energy Storage, 159, 121897(2026).
https://doi.org/10.1016/j.est.2026.121897
Moroz, M., Tesfaye, F., Demchenko, P., Prokhorenko, M., Rudyk, B., Pereviznyk, O., Mastronardo, E., Lindberg, D., Reshetnyak, O. and Hupa, L., Phase Equilibria and Thermodynamic Properties of Selected Compounds in the Ag–Ga–S–AgBr System for Modern Application in Energy Conversion Devices, Minerals, Met. Mater. Series, 257–268 (2024).
https://doi.org/10.1007/978-3-031-50244-6_23
Munirathnam, R., Farheen, S. M. R., Manjunatha, S., Manjunatha, H. C., Vidya, Y. S., Sridhar, K. N., Seenappa, L., Veera, R. M. S. And Krishnaveni, S., Tulsi mediated green synthesis of zinc doped CeO2 for super capacitor and display applications, J. Sci. Adv. Mater. Dev., 8(2), 100551 (2023).
https://doi.org/10.1016/j.jsamd.2023.100551
Nandagudi, A., Nagarajarao, S. H., Santosh, M. S., Basavaraja, B. M., Malode, S. J., Mascarenhas, R. J. and Shetti, N. P., Hydrothermal synthesis of transition metal oxides, transition metal oxide/carbonaceous material nanocomposites for supercapacitor applications, Mater. Today Sustain., 19, 100214(2022).
https://doi.org/10.1016/j.mtsust.2022.100214
Nazari, N., Mirzaee, S., Malek Khachatourian, A., Golmohammad, M., Javanmard, A., Sarraf-Mamoory, R., Zahrhuber, R. and Unterweger, C., Synthesis of CuO-ZnO/N, P-doped 3D rGO hybrid supercapacitive electrode: Fabrication and electrochemical characterization, Solid State Sci., 173, 108186(2026).
https://doi.org/10.1016/j.solidstatesciences.2025.108186
Panchal, P., Rauwel, P., Sharma, S., Nehra, S. P., Estephan, E., Praakle, K. and Rauwel, E., Ocimum tenuiflorum leaf-mediated graphitic carbon nitride and ZnO/GCN nanohybrid: a sustainable approach for environmental applications, Environ. Sci. Pollut. Res., 32(15), 9945–9965(2025).
https://doi.org/10.1007/s11356-025-36299-2
Pandey, P., Joshi, C. S. and Choubey, A. K., Lemon juice assisted synthesis of ternary ZnO@CuO@PANI nanocomposite as an efficient dielectric material for high-frequency applications, Polym. Bulletin, 83(8), 429 (2026).
https://doi.org/10.1007/s00289-026-06492-5
Pooja, K. R., Chikkatti, B. S., Sajjan, A. M., Manjanna, J. and Nagaraju, G., Engineering of β-Cu2V2O7 nanostructures for bifuntional use in environmental monitoring and supercapacitor applications, J. Ind. Chem. Soc., 102(10), 102040(2025).
https://doi.org/10.1016/j.jics.2025.102040
Rahman, M. M., Alam, M. M. and Asiri, A. M., Highly sensitive sensor probe development with ZCCO nano-capsule composites for the selective detection of unsafe methanol chemical by electrochemical technique, Appl. Nanosci., 12(5), 1571–1584(2022).
https://doi.org/10.1007/s13204-022-02354-4
Revathi, M., Nithya, G., Gunasekaran, S. S., Dhanalakshmi, E., Rajesh, P. and Lee, C. W., One-Pot Dual-Phytochemical Synthesis of Nickel Oxide Nanoparticles from Eclipta prostrata and Ocimum tenuiflorum as a Green Electrode for High-Performance Pseudo-Capacitor, JOM, 78(2), 1623–1632 (2026).
https://doi.org/10.1007/s11837-025-07939-2
Salamon, J., Simi, A., Prabu, H. J., Sahayaraj, A. F., Kennedy, A. J. S. and Johnson, I., Synthesis and Characterization of rGO-ZnO/Elwendia persica Seed Reinforced Hybrid Nanocomposite for High-Performance Supercapacitor Applications, J. Inorg. Organomet. Polym. Mater., 35(1), 342–355(2025).
https://doi.org/10.1007/s10904-024-03293-z
Sarker, M. I. R., Rahman, M. L., Hossain, M. J., Biswas, B., Ahmed, M. F., Jahan, S. A. and Sharmin, N., Multifunctional CoCuFe2O4 decorated GO & ZnS nanocomposites for halogen light & sunlight assisted photocatalytic degradation (Dye & Antibiotic) and humidity sensing: Microstructural, optical and electromagnetic properties, Mater. Sci. Eng. B, 326, 119168 (2026).
https://doi.org/10.1016/j.mseb.2025.119168
Singh, A. K., Ocimum sanctum mediated phytosynthesis of metallic nanoparticles: A review, Biores. Technol. Rep., 19, 101118(2022).
https://doi.org/10.1016/j.biteb.2022.101118
Soundarraj, C., Sumathi, T., Sivakumar, G., Parkavi, S., Sridevi, O. A. and Guganathan, L., Enhanced supercapacitor and photocatalytic performance of Zn doped nickel molybdate nanoparticles, Nanotechnol. Environ. Eng., 11(2), 63(2026).
https://doi.org/10.1007/s41204-026-00539-8
Surya, R., Sakthinathan, S., Meenakshi, G. A., Arumugam, B., Venkatesh, K. and Chiu, T. W., Synthesis of a novel p-type delafossite CuInO2 flowers anchored on Ti3C2 sheetsas a positive electrode for high performance asymmetric supercapacitor, Ceram. Int., 51(16), 22810–22819(2025).
https://doi.org/10.1016/j.ceramint.2025.01.562
Tian, F., Li, H., Wang, B., Cui, Y., Zheng, X., Wang, L., He, Z., Wang, S. and Liu, X., Co,N and Cu,N Co-doped ZnS with rich sulfur vacancies for high-performance supercapacitors, J. Energy Storage, 151, 120591 (2026).
https://doi.org/10.1016/j.est.2026.120591
Viswanathan, A., Manohar, A. and Aravindan, V., High energy and durable PANI, CuO and ZnO nanocomposites for aqueous/organic supercapacitors and their H+/NH+4 ions co-intercalation, Sci. Rep., 16(1), 15700(2026).
https://doi.org/10.1038/s41598-026-45954-8
Vusenappagari, R. and Kumar, B. D., Green combustion synthesised Zn/NiO nanocomposite for photocatalytic and supercapacitor applications, Int. J. Environ. Anal. Chem., 105(18), 7220–7239(2025).
https://doi.org/10.1080/03067319.2024.2440807
Yadav, S., Kaur, R. and Singh, P., Biosynthesis of zinc-copper mixed metal oxide nanoparticles using button-lac extract: A novel approach to combat antimicrobial resistance, Microbial Pathogenesis, 215, 108482(2026).
