Hollow Ni_0.5Zn_0.5Fe₂O₄/C/Ni microspheres with excellent microwave absorption properties

Abstract

The development of highly efficient microwave absorbers presents a significant challenge, driven by the growing issue of severe electromagnetic pollution. In this context, precise structural design emerges as a decisive factor for enhancing the microwave absorption capabilities. In this work, the hollow Ni_0.5Zn_0.5Fe₂O₄/C/Ni microspheres were fabricated through hydrothermal method, calcination treatment and further annealing. The results of the morphology observation demonstrate that the heterogeneous Ni_0.5Zn_0.5Fe₂O₄/C/Ni composites are hollow microspheres, consisting of many nanoparticles. Strikingly, the appearance of metallic Ni alongside increased carbon graphitization results from the partial reduction of Ni²⁺ by carbon during high-temperature annealing in the Ar atmosphere, which can be beneficial to the dielectric loss. The hollow Ni_0.5Zn_0.5Fe₂O₄/C/Ni microspheres possess outstanding microwave absorption capabilities, mainly owning to the better interface and dipole polarization, eddy current loss, conduction loss and natural resonance loss, multiply reflection and scattering between the microspheres. The hollow Ni_0.5Zn_0.5Fe₂O₄/C/Ni microspheres annealed at 700 °C exhibited an optimal reflection loss (RL) value of -35.79 dB at 2.5 mm and an effective absorption bandwidth (EAB) of 5.29 GHz at 2.0 mm. The present study reveals a design approach for heterostructures, which offers novel insights into the fabrication of high-performance microwave absorbing materials.

Keywords

Ferrite / hollow microspheres / graphitization degree / microwave absorption

References

[1] Derakhshani M,Jazirehpour M.Structural, magnetic, and gigahertz-range electromagnetic wave absorption properties of bulk Ni-Zn ferrite.Sci Rep2021;11:9468 PMCID:PMC8096849

[2] Ding D,Li X.Rational design of core-shell Co@C microspheres for high-performance microwave absorption.Carbon2017;111:722-32

[3] Zhao D,Shen Z.Fabrication and microwave absorbing properties of Ni-Zn spinel ferrites.J Alloys Compd2009;480:634-8

[4] Zhang Y,Zeng Y.An urchin‐inspired broadband and ultralight microwave absorber.Adv Funct Mater2025;35:2419943

[5] Xiang L,Rao Y.A simple strategy to develop heterostructured carbon paper/Co nanoparticles composites with lightweight, tunable and broadband microwave absorption.Mater Today Phys2023;34:101030

[6] Xu P,Qi D,Yue X.Egg white-derived carbon/magnetic nanoparticles/water-soluble graphene oxide composite with homogeneous structure as an excellent electromagnetic wave absorber.J Mater Chem C2021;9:9292-301

[7] Shao C,Shi Y,You C.Dielectric-magnetic synergy in ferrite/carbon composites for electromagnetic microwave absorption.Nano Res2025;18:94907815

[8] Guo J,Chen Z.Electrostatic self-assembled ceramic magnetic Ti₃C₂T_x nanocomposites reinforced with hollow Fe₃O₄ particles for strong and broadband absorption of electromagnetic waves.Ceram Int2025;51:29283-91

[9] Luo N,Ni Z,Fu Q.Preparation of reduced graphene oxide aerogel microspheres with excellent electromagnetic microwave absorption performance.Carbon2025;243:120466

[10] Wei H,Li W.Lightweight, flexible, heat resistant and thermal insulating aramid nanofiber/magnetic carbon nanotube interpenetrating network aerogel for microwave absorption in complex environments.Carbon2024;225:119115

[11] Zhu S,Ni J.Magnetic and microwave absorption properties of Ni_0.6Zn_0.4Fe₂O₄/SrFe₁₂O₁₉ composites.Mater Chem Phys2022;288:126398

[12] Zhao Q,Rong H.Ni-Zn 18H ferrite materials with abundant structural defects for waveband-tunable electromagnetic wave absorption.Ceram Int2025;51:31917-25

[13] Ibrahim RS,Azab AA.CuO/MFe₂O₄ (M = Co, Ni and Fe) ferrite nanocomposites: synthesis, characterization, optical and magnetic properties for diverse applications.Appl Phys A2025;131:9050

[14] Wang C,Wang X,Xie A.Synthesis of novel NiZn-ferrite/polyaniline nanocomposites and their microwave absorption properties.Mater Sci Semicond Process2013;16:77-82

[15] Wahaab FA,Rostami A.Microwave absorption performance of Ni_0.5Zn_0.5Fe₂O₄ nanoclusters at 8.2-18 GHz frequency.Indian J Phys2022;96:723-33

[16] Singh S,Srivastava R,Kumar R.Improved growth of nano tin ferrites with their decoration on carbon foam for wastewater treatment.Environ Nanotechnol Monit Manag2021;16:100546

[17] Bychanok D,Sanchez-sanchez A.Hollow carbon spheres in microwaves: Bio inspired absorbing coating.Appl Phys Lett2016;108:013701

[18] Tang Y,Zhang L.Novel carbon encapsulated zinc ferrite/MWCNTs composite: preparation and low-frequency microwave absorption investigation.Ceram Int2020;46:28250-61

[19] Zong M,Zhang N.Reduced graphene oxide-Ni_0.5Zn_0.5Fe₂O₄ composite: synthesis and electromagnetic absorption properties.Mater Lett2015;145:115-9

[20] Zhou X,Li L.Preparation of nanocrystalline-coated carbon nanotube/Ni_0.5Zn_0.5Fe₂O₄ composite with excellent electromagnetic property as microwave absorber.J Phys D Appl Phys2013;46:145002

[21] Li Z.Microwave absorption properties and mechanism for hollow Fe₃O₄ nanosphere composites.J Magn Magn Mater2015;387:131-8

[22] Aslam MA,Ding W.Dimensionality determined microwave absorption properties in ferrite/bio-carbon composites.Ceram Int2021;47:27496-502

[23] Bao S,Bu X,Jiang Z.Combinatorial structural engineering of multichannel hierarchical hollow microspheres assembled from centripetal Fe/C nanosheets to achieve effective integration of sound absorption and microwave absorption.ACS Appl Mater Interfaces2023;15:13565-75

[24] Ge J,Liu L.Optimizing the electromagnetic wave absorption performance of designed hollow CoFe₂O₄/CoFe@C microspheres.J Mater Sci Technol2021;81:190-202

[25] Sui M,Lou H.Synthesis of hollow Fe₃O₄ particles via one-step solvothermal approach for microwave absorption materials: effect of reactant concentration, reaction temperature and reaction time.J Mater Sci Mater Electron2018;29:7539-50

[26] Mandal D,Mandal K.Electromagnetic wave trapping in NiFe₂O₄ nano-hollow spheres: an efficient microwave absorber.J Magn Magn Mater2019;485:43-8

[27] Zhu X,Pan F.Covalent organic framework-derived hollow core-shell Fe/Fe₃O₄@porous carbon composites with corrosion resistance for lightweight and efficient microwave absorption.Compos Commun2021;25:100731

[28] Zhang M,Zi Z.Magnetic and microwave absorption properties of Ni_1-xZn_xFe₂O₄ nanocrystalline synthesized by sol-gel method.Sci China Technol Sci2013;56:13-9

[29] Xu Y,Weng S.Rationally designed Ni₂P/Ni/C as a positive electrode for high-performance hybrid supercapacitors.New J Chem2020;44:6810-7

[30] Okamura M,Toda M.Acid-catalyzed reactions on flexible polycyclic aromatic carbon in amorphous carbon.Chem Mater2006;18:3039-45

[31] Zhou X,Zhang X.Controllable synthesis of Ni/NiO@porous carbon hybrid composites towards remarkable electromagnetic wave absorption and wide absorption bandwidth.J Mater Sci Technol2021;87:120-32

[32] Bhattacharjee K,Das GC,Chattopadhyay KK.Effect of particle size distribution on the structure, hyperfine, and magnetic properties of Ni_0.5Zn_0.5Fe₂O₄ nanopowders.J Appl Phys2014;116:233907

[33] Anupama M,Dhananjaya N.Investigation on impedance response and dielectric relaxation of Ni-Zn ferrites prepared by self-combustion technique.J Alloys Compd2017;706:554-61

[34] Gómez CA, Barrero Meneses CA, Jaén JA. Raman, infrared and Mössbauer spectroscopic studies of solid-state synthesized Ni-Zn ferrites.J Magn Magn Mater2020;505:166710

[35] Li W,Niu X.Fe-Fe₃C/C microspheres as a lightweight microwave absorbent.RSC Adv2016;6:24820-6

[36] Cheng Y,Yang Z.An unusual route to grow carbon shell on Fe₃O₄ microspheres with enhanced microwave absorption.J Alloys Compd2018;762:463-72

[37] Li Z,Wang H,Xing C.General synthesis of homogeneous hollow core-shell ferrite microspheres.J Phys Chem C2009;113:2792-7

[38] Hao A,He S.Enhanced resistive switching and magnetic properties of Gd-doped NiFe₂O₄ thin films prepared by chemical solution deposition method.Mater Sci Eng B2018;229:86-95

[39] Zhai Y,Xu G,Liu X.Depolymerization of lignin via a non-precious Ni-Fe alloy catalyst supported on activated carbon.Green Chem2017;19:1895-903

[40] Yun X,Feng L.Microwave absorption enhancement of e-Fe₃O₄@C microspheres by core surface modification.J Alloys Compd2020;835:155307

[41] Liu R,Duan L.Effect of Fe²⁺/Fe³⁺ ratio on photocatalytic activities of Zn_1-xFe_xO nanoparticles fabricated by the auto combustion method.Ceram Int2020;46:1-7

[42] Jia Z,Yu B,Pan J.Tunable Co/ZnO/C@MWCNTs based on carbon nanotube-coated MOF with excellent microwave absorption properties.J Mater Sci Technol2022;127:153-63

[43] Liu Y,Jiang K,Lv T.Controllable synthesis of elliptical Fe₃O₄@C and Fe₃O₄/Fe@C nanorings for plasmon resonance-enhanced microwave absorption.J Mater Chem C2016;4:7316-23

[44] Wang Y,Wu C.Ultra-thin Ni@nitrogen-doped polyaniline-derived carbon composites with broadband electromagnetic wave absorption.New J Chem2023;47:17032-41

[45] Zang J,Li Z.Excellent microwave absorption of porous rod spinel by exceeding the Snoek limit via fibrosis and grain refinements.J Mater Chem C2024;12:18458-71

[46] Zhou J,Wang Y.Enhanced microwave absorption properties of (1-x)CoFe₂O₄/_xCoFe composites at multiple frequency bands.J Magn Magn Mater2020;493:165699

[47] Zhang W,Hu J,Yan W.Enhancing electromagnetic wave absorption performance through co-regulation of microstructure and spatial orientation of RE-Ni MOF.Chem Eng J2023;478:147414

[48] Luo K,Xu C.Construction of one-dimensional hierarchical MoS₂/Ni₃S₂ composites with enhanced interfacial polarization and improved wideband microwave absorption.J Mater Sci Technol2024;178:22-8

[49] Yang P,Ruan H.Amorphous/Graphitic carbon phase engineering of corrosion-resistant Fe@C Core-Shell nanowires for optimized dipole polarization and enhanced microwave absorption.Chem Eng J2024;492:152253

[50] Gao Y,Jia X.Orientation architecture engineering for enhanced electromagnetic wave absorption and active-passive infrared camouflage performances.Adv Funct Mater2025;35:2508442

[51] Pan J,Wang M.Shape anisotropic Fe₃O₄ nanotubes for efficient microwave absorption.Nano Res2020;13:621-9

[52] Zhang N,Wang M.3D ferromagnetic graphene nanocomposites with ZnO nanorods and Fe₃O₄ nanoparticles co-decorated for efficient electromagnetic wave absorption.Compos Part B Eng2018;136:135-42

[53] Zhang M,Xin Z.In situ reduced multi-core yolk-shell Co@C nanospheres for broadband microwave absorption.Materials2021;14:4610

[54] Wang T,Zhu J,Zhang L.Deep understanding of impedance matching and quarter wavelength theory in electromagnetic wave absorption.J Colloid Interface Sci2021;595:1-5

[55] Gai L,Song G.Construction of core-shell PPy@MoS₂ with nanotube-like heterostructures for electromagnetic wave absorption: Assembly and enhanced mechanism.Compos Part A Appl Sci Manuf2020;136:105965

[56] Huang X,Rao W,Song B.Tunable electromagnetic properties and enhanced microwave absorption ability of flaky graphite/cobalt zinc ferrite composites.J Alloys Compd2016;662:409-14

[57] Yan L,Zhang Y.Frequency-tunable microwave absorption via balanced impedance matching in Zn_0.35Ni_0.65Fe₂O₄/Ni-Cu multiphase ferrite composites.J Alloys Compd2025;1035:181614

[58] Bala M,Tyagi S.Enhancing X-band microwave absorption properties with nickel ferrite and carbon-based composites.Ceram Int2024;50:34123-32

[59] Ji X,Xu Z.Facile synthesis of pine needle-derived carbon/CoFe₂/CoFe₂O₄ composites with precisely tunable microwave attenuation efficiency.Mater Today Nano2025;32:100707

[60] Zhang Y,Wang B,Wang Y.Scalable mechanochemical synthesis of bifunctional MnZn ferrite/expanded graphite composites for efficient microwave absorption and corrosion resistance.J Mater Chem C2026;14:743-53

[61] Xu J,Li Q.Wrinkled Fe₃O₄@C magnetic composite microspheres: regulation of magnetic content and their microwave absorbing performance.J Colloid Interface Sci2021;601:397-410