TY - JOUR

T1 - Synthesis and NEXAFS and XPS Characterization of Pyrochlore-Type Bi1.865Co1/2Fe1/2Ta2O9+Δ

AU - Zhuk, N.A.

AU - Nekipelov, S.V.

AU - Petrova, O.V.

AU - Koroleva, A.V.

AU - Lebedev, A.M.

AU - Makeev, B.A.

N1 - Export Date: 10 November 2024 Сведения о финансировании: Ministry of Science and Higher Education of the Russian Federation, 075-15-2021-1351 Сведения о финансировании: Ministry of Science and Higher Education of the Russian Federation Текст о финансировании 1: The NEXAFS study was carried out within the framework of the state budget topic 122040400069-8 and also with the financial support of the Ministry of Science and Higher Education of Russia under agreement No. 075-15-2021-1351.

PY - 2024/9/19

Y1 - 2024/9/19

N2 - A cubic pyrochlore with the composition Bi1.865Co1/2Fe1/2Ta2O9+Δ (space group Fd-3m, a = 10.5013(8) Å) was synthesized from oxide precursors using solid-phase reactions. These ceramics are characterized by a porous microstructure formed by randomly oriented grains of an elongated shape with a longitudinal size of 0.5–1 µm. The electronic state of cobalt and iron ions in oxide ceramics was studied by NEXAFS and XPS spectroscopy. The parameters of the XPS spectra of Bi4f, Bi5d, Ta4f, Co2p, and Fe2p ionization thresholds for a complex pyrochlore were compared with the parameters of the corresponding oxides of the transition elements. The energy position of the XPS-Ta4f and -Ta5p spectra is shifted towards lower energies compared to the binding energy in tantalum(V) oxide by 0.75 eV. According to XPS spectroscopy, bismuth and tantalum cations have the corresponding effective charge of +3 and +(5-δ). The NEXAFS-Fe2p spectrum of ceramics coincides with the spectrum of Fe2O3 in its main spectrum characteristics and indicates the content of iron ions in the oxide ceramics in the form of octahedral Fe(III) ions, and according to the character of the Co2p spectrum, cobalt ions are predominantly in the Co(II) state. © 2024 by the authors.

AB - A cubic pyrochlore with the composition Bi1.865Co1/2Fe1/2Ta2O9+Δ (space group Fd-3m, a = 10.5013(8) Å) was synthesized from oxide precursors using solid-phase reactions. These ceramics are characterized by a porous microstructure formed by randomly oriented grains of an elongated shape with a longitudinal size of 0.5–1 µm. The electronic state of cobalt and iron ions in oxide ceramics was studied by NEXAFS and XPS spectroscopy. The parameters of the XPS spectra of Bi4f, Bi5d, Ta4f, Co2p, and Fe2p ionization thresholds for a complex pyrochlore were compared with the parameters of the corresponding oxides of the transition elements. The energy position of the XPS-Ta4f and -Ta5p spectra is shifted towards lower energies compared to the binding energy in tantalum(V) oxide by 0.75 eV. According to XPS spectroscopy, bismuth and tantalum cations have the corresponding effective charge of +3 and +(5-δ). The NEXAFS-Fe2p spectrum of ceramics coincides with the spectrum of Fe2O3 in its main spectrum characteristics and indicates the content of iron ions in the oxide ceramics in the form of octahedral Fe(III) ions, and according to the character of the Co2p spectrum, cobalt ions are predominantly in the Co(II) state. © 2024 by the authors.

KW - NEXAFS

KW - pyrochlore

KW - transition elements

KW - XPS

UR - https://www.mendeley.com/catalogue/8a6456d9-921e-340b-9d31-0eda71ded2c6/

U2 - 10.3390/chemistry6050062

DO - 10.3390/chemistry6050062

M3 - статья

VL - 6

SP - 1078

EP - 1088

JO - Chemistry (Switzerland)

JF - Chemistry (Switzerland)

SN - 2624-8549

IS - 5

ER -