Structural, dielectric, magnetic and sonophotocatalytic properties of M-type BaFe12O19 hexaferrite synthesized by solution combustion method

Structural, dielectric, magnetic and sonophotocatalytic properties of M-type BaFe12O19 hexaferrite synthesized by solution combustion method

Článek WoS

M-type barium hexaferrite (BaFe12O19) was synthesized via a self-sustaining solution combustion method followed by short-time calcination at 1000 degrees C. The obtained material exhibits a single-phase magnetoplumbite-type structure (P63/mmc) with a high degree of crystallinity and an average crystallite size of approximately 58 nm. SEM and EDX analyses confirmed a porous morphology and a stoichiometric Ba:Fe:O composition without detectable impurity phases. Raman spectroscopy and XPS investigations confirmed Fe3+ to be the dominant oxidation state, while surface-sensitive measurements indicate the presence of defect-modified oxygen-containing surface states that may contribute to localized electronic states within the band gap. Optical measurements revealed a direct band gap of 2.02 eV and an Urbach energy of 0.16 eV, indicating a moderate degree of structural disorder. Magnetic characterization showed a ferrimagnetic response with a high coercivity (Hc ti 3755 Oe) and a large magnetocrystalline anisotropy (Keff ti 2.9 x 106 erg/cm3), consistent with Mossbauer spectra that resolve five distinct Fe3+ sublattices (12k, 4f1, 4f2, 2a, 2b). The dielectric spectra exhibited a frequency-and temperature-dependent dispersion typical of ferrites, governed by Maxwell-Wagner interfacial polarization and hopping conduction between Fe2+/Fe3+ sites. The ac conductivity followed Jonscher's power law and was dominated by a correlated barrier hopping (CBH) mechanism. The BaFe12O19 catalyst demonstrated pronounced activity in photocatalytic, sonocatalytic, and in particular sonophotocatalytic degradation of methylene blue (MB), reaching ti 92% decolorization within 60 min with an apparent rate constant of 0.0397 min-1. The enhanced performance under combined light and ultrasonic irradiation originates from the interplay of photoexcitation, magnetostrictive and piezoelectric-like responses, and cavitation-induced charge modulation. Local band bending under acoustic deformation enables the participation of electrons in O2 reduction despite the nominally weakly reducing conduction band (ECB ti +0.20 eV), while defect-modified surface electronic states mediate efficient interfacial charge transfer. These findings reveal a synergistic activation mechanism in which hole-driven oxidation and electron-assisted radical generation coexist, highlighting BaFe12O19 as a multifunctional magneto-piezo-photocatalyst with stable dielectric and magnetic properties suitable for advanced environmental applications.

M-type barium hexaferrite (BaFe12O19) was synthesized via a self-sustaining solution combustion method followed by short-time calcination at 1000 degrees C. The obtained material exhibits a single-phase magnetoplumbite-type structure (P63/mmc) with a high degree of crystallinity and an average crystallite size of approximately 58 nm. SEM and EDX analyses confirmed a porous morphology and a stoichiometric Ba:Fe:O composition without detectable impurity phases. Raman spectroscopy and XPS investigations confirmed Fe3+ to be the dominant oxidation state, while surface-sensitive measurements indicate the presence of defect-modified oxygen-containing surface states that may contribute to localized electronic states within the band gap. Optical measurements revealed a direct band gap of 2.02 eV and an Urbach energy of 0.16 eV, indicating a moderate degree of structural disorder. Magnetic characterization showed a ferrimagnetic response with a high coercivity (Hc ti 3755 Oe) and a large magnetocrystalline anisotropy (Keff ti 2.9 x 106 erg/cm3), consistent with Mossbauer spectra that resolve five distinct Fe3+ sublattices (12k, 4f1, 4f2, 2a, 2b). The dielectric spectra exhibited a frequency-and temperature-dependent dispersion typical of ferrites, governed by Maxwell-Wagner interfacial polarization and hopping conduction between Fe2+/Fe3+ sites. The ac conductivity followed Jonscher's power law and was dominated by a correlated barrier hopping (CBH) mechanism. The BaFe12O19 catalyst demonstrated pronounced activity in photocatalytic, sonocatalytic, and in particular sonophotocatalytic degradation of methylene blue (MB), reaching ti 92% decolorization within 60 min with an apparent rate constant of 0.0397 min-1. The enhanced performance under combined light and ultrasonic irradiation originates from the interplay of photoexcitation, magnetostrictive and piezoelectric-like responses, and cavitation-induced charge modulation. Local band bending under acoustic deformation enables the participation of electrons in O2 reduction despite the nominally weakly reducing conduction band (ECB ti +0.20 eV), while defect-modified surface electronic states mediate efficient interfacial charge transfer. These findings reveal a synergistic activation mechanism in which hole-driven oxidation and electron-assisted radical generation coexist, highlighting BaFe12O19 as a multifunctional magneto-piezo-photocatalyst with stable dielectric and magnetic properties suitable for advanced environmental applications.

M-type hexaferrite, Sonophotocatalysis, Ultrasonic activation, Band bending, Reactive oxygen species, Methylene blue degradation, Piezo-magnetostrictive effects, Energy band structure

M-type hexaferrite, Sonophotocatalysis, Ultrasonic activation, Band bending, Reactive oxygen species, Methylene blue degradation, Piezo-magnetostrictive effects, Energy band structure

ALIKHANOV, N.; RABADANOVA, A.; MAGOMEDOVA, A.; ABDULKERIMOV, M.; GYULAKHMEDOV, R.; SHUAIBOV, A.; SELIMOV, D.; SOBOLA, D.; RAMAZANOV, S.; ABDULVAKHIDOV, K.; KUBRIN, S.; ORUDZHEV, F.

2026

15.01.2026

Elsevier

Surfaces and Interfaces

81

15.01.2026

Nizozemsko

1

17

17

https://www.sciencedirect.com/science/article/pii/S2468023025026562