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<p>The magnetic, dielectric and photocatalytic properties of Fe and Ni co-doped Co<sub>3</sub>O<sub>4</sub> nanoparticles (NPs) were studied in detail. XRD was done for the phase formation and structural analysis, which confirmed pure spinel phase of Co<sub>3</sub>O<sub>4</sub> using Rietveld refinement. The average crystallite size was calculated using refinement data which showed an increase from 16 to 32&#xa0;nm with co-doping due to increased crystal growth and defects. Surface morphology was studied by using TEM analysis which revealed non-spherical shaped NPs with dense agglomeration having average particles size of 120&#xa0;nm for undoped and 137&#xa0;nm for FN44 co-doped, respectively. The increase in average particle size with co-doping is associated with increased crystal growth caused by co-dopants. Magnetic measurements indicate the onset of ferromagnetism (FM) with co-doping which gets strengthen with increasing Fe doping and maximum magnetization was attained for FN62 sample (6% Fe and 2% Ni). The ZFC/FC measurements showed T<sub>N</sub> transition at 42&#xa0;K for undoped NPs which is shifted towards lower temperatures with co-doping. An irreversible ZFC/FC behavior is observed for co-doped samples which also indicates the presence of FM behavior. Photodegradation efficiency was tested using time dependent photodegradation experiment performed against MO-dye, which revealed a rapid and increased degradation efficiency with co-doping attributed to increased charge carrier concentration. FN44 sample (4% Fe and 4% Ni) showed maximum and fast degradation percentage of 89% with 81% degradation in just 30&#xa0;min, which is attributed to increased electron-hole recombination caused by Fe ions. Frequency-dependent dielectric measurements revealed an abrupt increase in dielectric constant of about 87.6% with co-doping. This is attributed to metallic Fe<sup>2+</sup> dopant atoms which causes an increase in charge concentration hence, supplying more charges for polarization, furthermore Fe<sup>3+</sup> and Fe<sup>2+</sup> ions favored small polaron hopping mechanism. AC conductivity was enhanced to 3.44 × 10<sup>− 7</sup> Sm<sup>− 1</sup> with co-doping as compared to 1.88 × 10<sup>− 8</sup> Sm<sup>− 1</sup> for undoped NPs, due to increased electrical conductivity and grain boundary effects caused by Fe and Ni ions.</p>

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Multifunctional Fe–Ni co-doped Co₃O₄ nanoparticles: a study on magnetic, dielectric and photocatalytic enhancement

  • 期刊论文

  • 发表日期：

    2026年1月5日

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  • M. Qasim,
  • K. Nadeem,
  • M. Shahid,
  • Hur Abbas,
  • J. Ping Liu,
  • M. Zareef Khan,
  • I. Hussain Gul

摘要

The magnetic, dielectric and photocatalytic properties of Fe and Ni co-doped Co3O4 nanoparticles (NPs) were studied in detail. XRD was done for the phase formation and structural analysis, which confirmed pure spinel phase of Co3O4 using Rietveld refinement. The average crystallite size was calculated using refinement data which showed an increase from 16 to 32 nm with co-doping due to increased crystal growth and defects. Surface morphology was studied by using TEM analysis which revealed non-spherical shaped NPs with dense agglomeration having average particles size of 120 nm for undoped and 137 nm for FN44 co-doped, respectively. The increase in average particle size with co-doping is associated with increased crystal growth caused by co-dopants. Magnetic measurements indicate the onset of ferromagnetism (FM) with co-doping which gets strengthen with increasing Fe doping and maximum magnetization was attained for FN62 sample (6% Fe and 2% Ni). The ZFC/FC measurements showed TN transition at 42 K for undoped NPs which is shifted towards lower temperatures with co-doping. An irreversible ZFC/FC behavior is observed for co-doped samples which also indicates the presence of FM behavior. Photodegradation efficiency was tested using time dependent photodegradation experiment performed against MO-dye, which revealed a rapid and increased degradation efficiency with co-doping attributed to increased charge carrier concentration. FN44 sample (4% Fe and 4% Ni) showed maximum and fast degradation percentage of 89% with 81% degradation in just 30 min, which is attributed to increased electron-hole recombination caused by Fe ions. Frequency-dependent dielectric measurements revealed an abrupt increase in dielectric constant of about 87.6% with co-doping. This is attributed to metallic Fe2+ dopant atoms which causes an increase in charge concentration hence, supplying more charges for polarization, furthermore Fe3+ and Fe2+ ions favored small polaron hopping mechanism. AC conductivity was enhanced to 3.44 × 10− 7 Sm− 1 with co-doping as compared to 1.88 × 10− 8 Sm− 1 for undoped NPs, due to increased electrical conductivity and grain boundary effects caused by Fe and Ni ions.