Green Synthesis and RSM Optimization of Endostemon viscosus-derived α-MoO₃ Nanostructures for Supercapacitor Applications
J. Environ. Nanotechnol., Volume 15, No 3 (September 2026) pp. 452-462
Abstract
This study introduces a sustainable plant-mediated strategy for preparing electrochemically active α-MoO₃ nanostructures using Endostemon viscosus leaf extract and evaluates their potential as supercapacitor electrode materials. The aqueous leaf extract was prepared from 10 g of dried leaves in 100 mL of distilled water at 80 °C for 30 min, followed by its reaction with ammonium heptamolybdate precursor solution and subsequent aging, washing, drying, and calcination. XRD confirmed well-crystallized orthorhombic α-MoO₃ with an average crystallite size of approximately 28 nm, while TGA indicated satisfactory thermal stability with 91.4% residual mass. FTIR confirmed characteristic Mo=O and Mo–O–Mo vibrations, and FE-SEM revealed agglomerated flake-/sheet-like nanostructures with interconnected porous regions. EDS showed 66.66 wt.% Mo and 33.34 wt.% O, while BET analysis yielded a specific surface area of approximately 118 m² g⁻¹ and an average pore diameter of 18 nm. Electrochemical measurements demonstrated a maximum specific capacitance of approximately 458 F g⁻¹ at 5 mV s⁻¹ from CV and 360 F g⁻¹ at 0.5 A g⁻¹ from GCD. The electrode retained 94.3% of its initial capacitance after 5000 cycles and exhibited low series and charge-transfer resistances of approximately 1.8 and 7.2 Ω, respectively. Overall, the developed α-MoO₃ nanostructures exhibited promising electrochemical performance for supercapacitor applications. Future studies should focus on developing complete two-electrode devices and evaluating energy density, power density, long-term cycling stability, and practical operating performance.
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Alotaibi, N. H., Manzoor, I., Abid, A. G., Shah, J. H., Mohammad, S., Kumar, O. P., Zadneprovskaya, E. V. and Allakhverdiev, S. I., MoO3/NiO bimetallic-N active sites in graphitic nitride sheet for enhanced water splitting and energy storage system, Int. J. Hydrogen Energy, 137, 1–12 (2025).
https://doi.org/10.1016/j.ijhydene.2025.05.059
Edlabadkar, A. P., Chaudhari, S., Harak, S. S., Vijayakumar, M., Nanthakumar, S. and Mayakannan, S., Optimising Tensile and Impact Strength of Polyethylene-based Nanocomposites with Graphene, Carbon and Hemp Fibers, Int. J. Veh. Struct. Syst., 18(1), 39–46 (2026).
https://doi.org/10.4273/ijvss.18.1.08
Eisa, M. H., Esaenwi, S., Okereke, B. O. and Obodo, R. M., Electrochemical engineering on redox-active MnO2 and MoO3 bonded in MXenes matrices for supercapacitor applications, Inorg. Chem. Commun., 185, 116082 (2026).
https://doi.org/10.1016/j.inoche.2025.116082
Ferozgandhi, K., Girirajan, M., Subramaniyan, S., Sangaraju, S., Ali, M., Raju, R., Shanmugaraj, G. and Sakkarapani, S., Graphitic carbon nitride quantum dot embedded with MoO3-GO nanosheets as electrode material for enhanced supercapacitor performance, J. Energy Storage, 113, 115743 (2025).
https://doi.org/10.1016/j.est.2025.115743
Ganvir, H. V, Hadidi, H. M., Saminathan, R., Bhagat, M. S., Krishnaraj, C. and Satishkumar, P., Green Sol–gel Synthesis of Cu/Co3O4 Nanocomposite Using Curcuma Longa Leaf Extract for High-performance Supercapacitor Electrodes, J. Environ. Nanotechnol., 15(1), 543–554 (2026).
https://doi.org/10.13074/jent.2026.03.2541993
Gottam, R. and Srinivasan, P., Composite electrode material of MoO3-MC-SiO2-PANI: Aqueous supercapacitor cell with high energy density, 1 V and 250,000 CD cycles, Polym. Adv. Technol., 32(6), 2465–2475 (2021).
https://doi.org/10.1002/pat.5276
Hemapriya, S., Velusamy, P., Sivaprakash, P. and Kim, I., Electroactive metal ion (Co2+) doped MoO3/CNS nanocomposite for high efficiency supercapacitor application, Electrochimica Acta, 573, 149450 (2026).
https://doi.org/10.1016/j.electacta.2026.149450
Kabir, M. F., Zubair, M. A., Ul-Hamid, A. and Islam, M. R., Enhancing redox activity and surface reactivity via hierarchical α-MoO3 nanobelt incorporation into layered WS2 nanosheets for high performance symmetric and asymmetric supercapacitors, Nanoscale, 17(44), 25555–25571 (2025).
https://doi.org/10.1039/d5nr03799a
Khan, M., Salman, M., Ullah, A., Ullah, N., Syed, A., Bahkali, A. H., Shah, A., Ali, R., Ling, Y. and Khan, M., Effect of hydrothermal reaction temperature on MoO3 nanostructure properties for enhanced electrochemical performance as an electrode material in supercapacitors, Ceram. Int., 50(19), 34943–34955 (2024).
https://doi.org/10.1016/j.ceramint.2024.06.303
Krishnasamy, B., Gladston, A. K., Sekar, C. B. and Selvaraju, M., Investigation on the thermal, mechanical, and morphological characterization of peepal fiber-reinforced epoxy composites enhanced with micro-particulate ziziphus mauritiana seed powder, Revista Materia, 31, e20250643 (2026).
https://doi.org/10.1590/1517-7076-RMAT-2025-0643
Meena, R., Bharathi, A., Gatasheh, M. K., Ahmed, N. A., Ravindran, B. and Murugesan, S., Green Synthesis of Silver and Chitosan–Silver Nanoparticles Using Endostemon viscosus Leaf Extract: Characterization and Biological Activities, J. Clust. Sci., 37(3), 67(2026a).
https://doi.org/10.1007/s10876-026-03022-1
Meena, R., Bharathi, A., Gatasheh, M. K., Anis, A. N., Natarajan, D., Ravindran, B. and Murugesan, S., In vitro anticancer and pharmaceutical potential of ethanolic leaf extract of Endostemon viscosus, J. Herb. Med., 55, 101081 (2026b).
https://doi.org/10.1016/j.hermed.2025.101081
Meena, R., Devaraj, R., Gatasheh, M., Ahamed, A., Ravindran, B. and Murugesan, S., Eco-Friendly Synthesis of Titanium Dioxide Nanoparticles from Endostemon viscosus Leaf Extract: Characterization and Evaluation of Biological Activities, Appl. Organomet. Chem., 40(3), e70540 (2026c).
https://doi.org/10.1002/aoc.70540
Ondrejka, P., Petrík, A., Husár, M., Straňovský, Á., Kemény, M., Sojková, M., Novák, P. and Mikolášek, M., Optimization of MoO3 microstructures through temperature control and KOH activation for improved supercapacitor electrode performance, Monatshefte Fur Chemie, 156(5), 577–582 (2025).
https://doi.org/10.1007/s00706-025-03318-4
Patil, A. R., Tawade, A. K., Kamble, G. U., Sharma, K. K. K., Kim, J. H. and Dalavi, D. S., Electrochemical insights into MoO3-PANI composites for enhanced energy storage, Ionics, 32(5), 5221–5231 (2026).
https://doi.org/10.1007/s11581-026-07074-1
Pradhan, D., Shetgaonkar, S. S., Fernandes, R. and Morajkar, P. P., Hierarchical defect engineered V2O5-x/MoO3-y microplates as efficient electrode material for enhanced supercapacitor performance, J. Energy Storage, 176, 123385 (2026).
https://doi.org/10.1016/j.est.2026.123385
Raza, A., Ali, M., Ayub, N., Atta, S. and Jawad, M., Chemical vapor deposition-based synthesis of binder-free nanostructure α-MoO3 electrode material for PES devices, Physica Scripta, 99(5), 055910(2024).
https://doi.org/10.1088/1402-4896/ad3502
Rout, S. K., Samal, P. K., Panigrahy, J., Nanda, P., Praharaj, S. and Rout, D., Enhanced cyclic stability of MoO3@BiFeO3 nanocomposites for long life supercapacitor electrodes, J. Alloys Compds., 1020, 179422 (2025).
https://doi.org/10.1016/j.jallcom.2025.179422
Roy, P., Saifullah, Zubair, M. A. and Islam, M. R., Tuning the electrochemical performance of a hierarchical MoO3/CdO binary heterostructure for supercapacitor applications, Nanoscale Adv., 7(18), 5681–5700 (2025).
https://doi.org/10.1039/d5na00491h
Saeed, M., Karamat, S., Alahmadi, A. N. M., Aman, M., Sabir, I., Kashif, M., Masud, M. I. and Ullah, F., Electrochemical behavior of biochar, molybdenum trioxide and graphene nanocomposite for supercapacitors, Res. Eng., 28, 108102 (2025).
https://doi.org/10.1016/j.rineng.2025.108102
Shalom, N., Haridass, R., Kulurkar, P. and Mayakannan, S., Development of Eco-Friendly Prosopis Juliflora Fiber-Reinforced Epoxy Composites with Mg (OH)2 and TiO2 Nanofillers for Improved Mechanical and Fire-Retardant Properties, Int. Res. J. Multidiscipl. Technovat., 8(4), 288–306 (2026).
https://doi.org/10.54392/irjmt26417
Shoeb, M., Mashkoor, F., Khan, J. A., Gondal, M. A., Kim, B. J. and Jeong, C., Three-dimensionally networked RGO-MoO3-MoS2/polyindole nanocomposite on woven carbon fiber for supercapacitor device and their improved charge storage mechanism, J. Energy Storage, 134, 118208 (2025).
https://doi.org/10.1016/j.est.2025.118208
Thirupathy, M., Suresh, S., Rajesh, P., Maithreyee, V., Rhoda, J. C., Nagaraja, K. S. and Karnan, C., Supercapacitor performance of binary metal oxide copper (II) oxide-β’-molybdenum oxide nanocomposites for energy storage applications, J. Alloys Compds., 1078, 189715 (2026).
https://doi.org/10.1016/j.jallcom.2026.189715
Vadivel, M., Hadidi, M. H., Saminathan, R., Bhagat, S. M. and Satishkumar, P., Synergistic TiO2 Nanosheets and Nitrogen-doped Carbon-coated NiCo2O4 Nanocomposite for High-performance Hybrid Supercapacitors, J. Environ. Nanotechnol., 15(1), 249–261 (2026).
https://doi.org/10.13074/jent.2026.03.2541992
Verma, V., Singh, R. S., Gupta, M. and Singh, A. K., Fermi-level tuning in graphene via green synthesized h-MoO3: Enhanced supercapacitor performance of h-MoO3 doped graphene, J. Alloys Compds., 1018, 179225 (2025).
https://doi.org/10.1016/j.jallcom.2025.179225
Wanchan, W., Yogesh, G. K., Yeetsorn, R., Maiket, Y. and Koinkar, P., Synthesis and characterization of synergetic Pd/MoO3–rGO hybrid material as efficient electrode for supercapacitor application, Mater. Chem. Phy., 331, 130134 (2025).
https://doi.org/10.1016/j.matchemphys.2024.130134
Zhang, Z., Shi, H., Zhuang, B., Luo, M. and Hu, Z., The microstrain-accompanied structural phase transition from h-MoO3 to α-MoO3 investigated by in situ X-ray diffraction, Beilstein J. Nanotechnol., 14, 692–700 (2023).
