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<p>The Sr<sub>0.5</sub>Sn<sub>0.5</sub>V<sub>2</sub>O<sub>6</sub>–SnO<sub>2</sub> composite was prepared by a solid-state route, and its crystal structure and physical properties were investigated. The X-ray diffraction confirmed the two-phase nature of the composite. One of the phases was assigned to a compound with a crystal structure related to that of foordite-type SnNb<sub>2</sub>O<sub>6</sub>. At room temperature, the dielectric constant ɛʹ of the composite (at 1&#xa0;kHz) has a value of ~ 2100, and the electrical conductivity σ has a small value (~ 3.4 × 10<sup>–3</sup> µS), which indicates the dominant role of the dielectric properties over the semiconductor ones. Impedance spectroscopy revealed that with increasing temperature, the capacitance of the grain interior increases due to thermal expansion. It exhibits two anomalies (at ~ 270&#xa0;°C and ~ 420&#xa0;°C) associated with the SnO₂ phase transition and oxygen vacancies. Meanwhile, the resistance of the grain interior, grain boundaries, and the Warburg element decreases with increasing temperature. TEM images revealed the variation of Sr<sub>0.5</sub>Sn<sub>0.5</sub>V<sub>2</sub>O<sub>6</sub> crystallite size in the range from 100 to 150&#xa0;nm. The study of the electrocatalytic properties of the composite revealed its moderate catalytic activity toward the water splitting reaction. Using the density functional theory (DFT), the thermodynamic stability of the composites was analyzed in the concentration range <i>x</i> = 0.0 – 1.0 with a step of <i>x</i> = 0.2 and it has been shown that all the compositions are thermodynamically metastable, even taking into account vibrational and configuration entropy terms, which explains the observed Sr<sub>0.5</sub>Sn<sub>0.5</sub>V<sub>2</sub>O<sub>6</sub> phase as a composite or a kinetically stabilized compound.</p>

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Physical properties and structure of the composite Sr0.5Sn0.5V2O6–SnO2

  • 期刊论文

  • 发表日期：

    2026年6月3日

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  • Ekaterina R. Kolomenskaya,
  • Kamaludin G. Abdulvakhidov,
  • Igor L. Shukaev,
  • Ilya V. Pankov,
  • Bogdan O. Protsenko,
  • Alexander V. Soldatov,
  • Bashir K. Abdulvakhidov

摘要

The Sr0.5Sn0.5V2O6–SnO2 composite was prepared by a solid-state route, and its crystal structure and physical properties were investigated. The X-ray diffraction confirmed the two-phase nature of the composite. One of the phases was assigned to a compound with a crystal structure related to that of foordite-type SnNb2O6. At room temperature, the dielectric constant ɛʹ of the composite (at 1 kHz) has a value of ~ 2100, and the electrical conductivity σ has a small value (~ 3.4 × 10–3 µS), which indicates the dominant role of the dielectric properties over the semiconductor ones. Impedance spectroscopy revealed that with increasing temperature, the capacitance of the grain interior increases due to thermal expansion. It exhibits two anomalies (at ~ 270 °C and ~ 420 °C) associated with the SnO₂ phase transition and oxygen vacancies. Meanwhile, the resistance of the grain interior, grain boundaries, and the Warburg element decreases with increasing temperature. TEM images revealed the variation of Sr0.5Sn0.5V2O6 crystallite size in the range from 100 to 150 nm. The study of the electrocatalytic properties of the composite revealed its moderate catalytic activity toward the water splitting reaction. Using the density functional theory (DFT), the thermodynamic stability of the composites was analyzed in the concentration range x = 0.0 – 1.0 with a step of x = 0.2 and it has been shown that all the compositions are thermodynamically metastable, even taking into account vibrational and configuration entropy terms, which explains the observed Sr0.5Sn0.5V2O6 phase as a composite or a kinetically stabilized compound.