Zn_xFe_2–xO₃ nanoparticles and composites are a focus area of research in nanotechnology, biotechnology, and material engineering. The functional properties of these nanomaterials depend on the scientific method of synthesizing and characterizing procedure. In this study, greater attention is invested on biological synthesis of Zn_xFe_2–xO₃nanoparticles and nanocomposite. For in vivo or in vitro study, properties, such as biocompatibility, reactivity, bio sensitivity, photosensitivity, and biodegradability are considered. Besides, the Ferrofluid and nanofluid of Zn_xFe_2–xO₃nanostructures are investigated for solar cells and photoconductors. More emphasis is given to the roles of nanotechnology in transforming Zn_xFe_2–xO₃ nanoparticles to photocatalytic activity. In addition, the impact of nanotechnology and surface effect on the photocatalytic activity of nanoparticles is discussed. Moreover, the significance of Zn_xFe_2–xO₃nanoparticles is highlighted for the applications in photovoltaic and solar cells.

Key Words: Biological method, Magnetic nanoparticles, Nanosensors, Nanotechnology, photo catalytic activity.

1. Teja AS, Koh PY. Synthesis, properties, and applications of magnetic iron oxide nanoparticles. Prog Cryst Growth Charact Mater. 2009;55(1–2):22–45. doi: 10.1016/j.pcrysgrow.2008.08.003. 2. Abd-Elsalam KA, Prasad R, Alghuthaymi MA, Ayyadurai N, Kumar A. Nanoparticles in modern antimicrobial and antiviral applications. Nanotechnology in Life Sciences. 2019;1–20. ISSN: 2523–8027. 3. Amjad M, Khan MI, Alwadai N, Irfan M, Albalawi H, Almuqrin AH, et al. Photovoltaic properties of ZnO films Co-doped with Mn and La to enhance solar cell efficiency. Nanomaterials (Base). 2021;127:1057. doi: 10.3390/nano12071057. 4. Mustapha S, Elabor R, Tijani JO, Egbosiuba TC, Amigun AT, Salihu AM, et al. Green magnetic nanoparticles for photocatalytic applications. In: Green Magnetic Nanoparticles (GMNPs). Elsevier. 2024;377–404. doi: 10.1016/B978-0-443-21895-8.00015-1. 5. Ashok A, Kennedy LJ, Vijaya JJ. Structural, optical and magnetic properties of Zn1-xMnxFe2O4 (0 ≤ x ≤ 0.5) spinel nano particles for transesterification of used cooking oil. J Alloys Compd. 2019;780:816–828. doi: 10.1016/j.jallcom.2018.11.390 6. Lassoued A. Synthesis and characterization of Zn-doped α-Fe2O3 nanoparticles with enhanced photocatalytic activities. J Mol Struct. 2021;1239:130489. doi: 10.1016/j.molstruc.2021.130489. 7. Govan J, Gun’ko YK. Recent advances in the application of magnetic nanoparticles as a support for homogeneous catalysts. Nanomaterials (Basel). 2014;4(2):222–224. doi: 10.3390/nano4020222. 8. Indira AC, Muthaian JR, Pandi M, Mohammad F, Al-Lohedan HA, Soleiman AA. Photocatalytic efficacy and degradation kinetics of chitosan-loaded Ce-TiO2 nanocomposite towards for rhodamine B dye. Catalysts. 2023;13(12):1506. doi: 10.3390/catal13121506. 9. Melinte V, Stroea L, Chibac-Scutaru AL. Polymer nanocomposites for photocatalytic applications. Catalysts. 2019;9(12):986. doi: 10.3390/catal9120986. 10. Sujatha K, Seethalakshmi T, Sudha AP, Shanmugasundaram OL. Photocatalytic activity of pure, Zn doped and surfactants assisted Zn doped SnO2 nanoparticles for degradation of cationic dye. Nano-Struct Nano-Objects. 2019;18:100305. doi: 10.1016/j.nanoso.2019.100305. 11. Kumar P, Deng ZY, Tsai PY, Chiu CY, Lin CW, Chaudhary P, et al. Enhanced visible-light photocatalytic activity of Fe3O4@ MoS2@ Au nanocomposites for methylene blue degradation through Plasmon-Induced charge transfer. Sep Purif Technol. 2024;342(6):126988. doi: 10.1016/j.seppur.2024.126988. 12. Zhang Y, Nayak TR, Hong H, Cai W. Biomedical applications of zinc oxide nanomaterials. Curr Mol Med. 2019;19(1):3–22. doi: 10.2174/1566524013666131111130058. 13. Das RK, Pachapur VL, Lonappan L, Naghdi M, Pulicharla R, Maiti S, et al. Biological synthesis of metallic nanoparticles: Plants, animals and microbial aspects. Nanotechnol Environ Eng. 2017;2:1–21. doi: 10.1007/s41204-017-0029-4. 14. Hasan pour A, Niyaifar M, Asan M, Amighian J. Synthesis and characterization of Fe3O4 and ZnO nanocomposites by the sol–gelmethod. J Magn Magn Mater. 2013;334:41–44. doi: 10.1016/j.jmmm.2013.01.016. 15. Kamali M, Xue Y, Khalaj M, Laats B, Teunckens R, Verbist M, et al. ZnO/γ-Fe2O3/Bentonite: An efficient solar-light active magnetic photocatalyst for the degradation of pharmaceutical active compounds. Molecules. 2022;27(10):3050. doi: 10.3390/molecules27103050. 16. Yang S, Jiang JT, Xu CY, Wang Y, Xu YY, Cao L, et al. Synthesis of Zn (II)-doped magnetite leaf-like nanorings for efficient electromagnetic wave absorption. Sci Rep. 2017;7:45480. doi: 10.1038/srep45480. 17. Simfukwe J, Mapasha RE, Braun A, Diale M. Exploring the stability and electronic properties of Zn-doped hematite surfaces for photoelectrochemical water splitting. J Phys Chem Solids. 2020;136:109159. doi: 10.1016/j.jpcs.2019.109159. 18. Zhang Y, Su P, Weathersby D, Zhang Q, Zheng J, Fan R, et al. Synthesis of γ-Fe2O3-ZnO-biochar nanocomposites for Rhodamine B removal. Appl Surf Sci. 2020;501:144217. doi: 10.1016/j.apsusc.2019.144217. 19. Kasparis G, Sangnier AP, Wang L, Efstathiou C, LaGrow AP, Sergides A, et al. Zn doped iron oxide nanoparticles with high magnetization and photothermal efficiency for cancer treatment. J Mater Chem B. 2022;11(4):787–801. doi: 10.1039/d2tb01338j. 20. Guo XH, Yang H, Guo GB. One-pot synthesis of Iron oxide doped carbon microsphere composites. Material science forum. 2018;932:76–80. doi: 10: 4028/www.scientific net/MSF.932.76.