Researchers Use Raman Spectroscopy to Study Phase Transition of Monoclinic Silver Dimolybdate Microrods at High Temperatures

Researchers at Universidade Federal do Maranhão in São Luís, Brazil, have conducted an in situ high-temperature Raman scattering study of monoclinic silver dimolybdate (m-Ag₂Mo₂O₇) microrods. The study, published in the Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy journal, explored the temperature-dependent behavior of the m-Ag₂Mo₂O₇ microrods and found an irreversible first-order structural phase transition at 698 K–723 K and a melting process at 773 K (1).

blue geometric shape abstract technology background | Image Credit: © monsitj - stock.adobe.com

The researchers obtained the m-Ag₂Mo₂O₇ microrods by using the conventional hydrothermal method at 423 K for 24 h. Then, they conducted structural and morphological characterization of the sample using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The Raman scattering measurements were performed on m-Ag₂Mo₂O₇ microrods to determine the phase transition, and doing so revealed changes in the Raman spectra, confirming the transition from the P21/c monoclinic structure to the P-1 triclinic structure.

Monoclinic silver dimolybdate (m-Ag₂Mo₂O₇) microrods have potential applications in various fields, such as catalysis, electrochemistry, and gas sensing. The study of their structural and morphological properties, as well as their temperature-dependent behavior, is important for understanding their potential applications and for developing new ones. The in situ high-temperature Raman scattering study of m-Ag₂Mo₂O₇ microrods presented in the article provides valuable insights into their phase transition behavior and melting process, which can inform future research on this subject.

Interestingly, no morphological changes were observed during the structural phase transition of the sample at 723 K. However, time-dependent optical microscopy at 773 K showed the growth of nanowires on the Ag₂Mo₂O₇ microrods in the triclinic structure. This study provides significant insights into the temperature-dependent behavior of m-Ag₂Mo₂O₇ microrods and their potential use in high-temperature applications.

This paper, with lead author J.V.B. Moura, indicated that Raman spectra provide important insights into the high-temperature phase transition behavior of m-Ag₂Mo₂O₇ microrods, which is essential for their practical applications in various fields. This study could lead to further research on the phase transition behavior of other materials and could potentially open up new avenues for their use in high-temperature applications.

Overall, this study highlights the importance of understanding the temperature-dependent behavior of materials and their potential for practical applications. The findings of this study could have significant implications in various fields, such as materials science, chemistry, and physics.

Reference

(1) Ferreira, A. N. C.; Ferreira, W. C.; Duarte, A. V.; Santos, C. C.; Freire, P. T. C.; Luz-Lima, C.; Moura, J. V. B. In situ high‐temperature Raman scattering study of monoclinic Ag₂Mo₂O₇ microrods. Spectrochimica Acta Part A: Mol. Biomol. Spectrosc. 2023, 295, 122632. DOI: 10.1016/j.saa.2023.122632