This study explores the photocatalytic behavior of 4c-Fe7Se8 (4c-FS) and 3c-Fe7Se8 (3c-FS) nanoparticles, which were synthesized through a solid-state method. X-ray diffraction (XRD) analysis verified their hexagonal crystal structure, with crystallite sizes calculated to be approximately 32 nm and 38 nm for 4c-FS and 3c-FS, respectively. FESEM analysis showed that the nanoparticles were agglomerated, exhibiting particle sizes around 256 nm (4c-FS) and 233 nm (3c-FS). Raman analysis identified distinct vibrational peaks at 218 cm−1 and 283 cm−1 for 4c-FS and 219 cm−1 and 285 cm−1 for 3c-FS. FTIR results indicated the appearance of triple bond–related vibrations, particularly C≡C or C≡N, at 2110 cm−1. Magnetic measurements performed using vibrating sample magnetometry (VSM) revealed a significant enhancement in coercivity at 15 K (2045 Oe for 4c-FS and 1693 Oe for 3c-FS) compared to their values at room temperature (90 Oe and 87 Oe), suggesting pronounced low-temperature magnetic anisotropy. The optical band gaps of 4c-FS and 3c-FS were estimated to be 1.68 eV and 1.78 eV, respectively, indicating their suitability for visible-light-driven photocatalysis. Under UV exposure, both materials demonstrated effective methylene blue (MB) degradation, with removal efficiencies reaching 91% for 4c-FS and 85% for 3c-FS. The degradation kinetics adhered to both pseudo-first-order (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10854_2025_15563_Article_IEq1.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">${k}_{1}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>k</mi> <mn>1</mn> </msub> </math></EquationSource> </InlineEquation> = 0.019 min−1 and 0.015 min−1) and pseudo-second-order models (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10854_2025_15563_Article_IEq2.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">${k}_{2}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>k</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation> = 0.098 min−1 and 0.077 min−1). These results underscore the potential of Fe7Se8 nanoparticles in applications focused on environmental purification and magnetic functionalities.

Photocatalytic performance and structural properties of Fe₇Se₈ nanoparticles synthesized by solid-state reaction method

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发表日期：

2025年8月18日

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Sunita J. Yadav,
Israr Ahmed Shaikh,
Santilata Sahoo,
D. V. Shah

摘要

This study explores the photocatalytic behavior of 4c-Fe₇Se₈ (4c-FS) and 3c-Fe₇Se₈ (3c-FS) nanoparticles, which were synthesized through a solid-state method. X-ray diffraction (XRD) analysis verified their hexagonal crystal structure, with crystallite sizes calculated to be approximately 32 nm and 38 nm for 4c-FS and 3c-FS, respectively. FESEM analysis showed that the nanoparticles were agglomerated, exhibiting particle sizes around 256 nm (4c-FS) and 233 nm (3c-FS). Raman analysis identified distinct vibrational peaks at 218 cm⁻¹ and 283 cm⁻¹ for 4c-FS and 219 cm⁻¹ and 285 cm⁻¹ for 3c-FS. FTIR results indicated the appearance of triple bond–related vibrations, particularly C≡C or C≡N, at 2110 cm⁻¹. Magnetic measurements performed using vibrating sample magnetometry (VSM) revealed a significant enhancement in coercivity at 15 K (2045 Oe for 4c-FS and 1693 Oe for 3c-FS) compared to their values at room temperature (90 Oe and 87 Oe), suggesting pronounced low-temperature magnetic anisotropy. The optical band gaps of 4c-FS and 3c-FS were estimated to be 1.68 eV and 1.78 eV, respectively, indicating their suitability for visible-light-driven photocatalysis. Under UV exposure, both materials demonstrated effective methylene blue (MB) degradation, with removal efficiencies reaching 91% for 4c-FS and 85% for 3c-FS. The degradation kinetics adhered to both pseudo-first-order ( ${k}_{1}$ $k_{1}$ = 0.019 min⁻¹ and 0.015 min⁻¹) and pseudo-second-order models ( ${k}_{2}$ $k_{2}$ = 0.098 min⁻¹ and 0.077 min⁻¹). These results underscore the potential of Fe₇Se₈ nanoparticles in applications focused on environmental purification and magnetic functionalities.

Photocatalytic performance and structural properties of Fe7Se8 nanoparticles synthesized by solid-state reaction method

摘要

Photocatalytic performance and structural properties of Fe₇Se₈ nanoparticles synthesized by solid-state reaction method