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<p>This research reports the temperature-dependent vibrational properties of cadmium tungstate (CdWO<sub>4</sub>) in its monoclinic structure using Raman spectroscopy. The density functional theory was employed to calculate the Raman mode assignments, band structure, and partial/projected density of states for the crystal. Experimental Raman spectroscopy measurements were conducted across a temperature range of 10–1000&#xa0;K, revealing that the CdWO<sub>4</sub> crystal maintains structural stability throughout this range. Principal component analysis and hierarchical cluster analysis were utilized to evaluate temperature ranges conducive to conformational changes, confirming the absence of phase transitions within the studied conditions. Additionally, the CdWO<sub>4</sub> crystal was explored as an electrocatalyst for the hydrogen evolution reaction. As an electrocatalyst, CdWO<sub>4</sub> exhibits an&#xa0;overpotential of 870&#xa0;mV&#xa0;(at 10&#xa0;mA&#xa0;cm⁻<sup>2</sup>) and a&#xa0;Tafel slope of 221&#xa0;mV dec⁻<sup>1</sup>. The moderate HER activity is attributed to the&#xa0;low electrochemical surface area (ECSA&#xa0;=&#xa0;1.34 cm<sup>2</sup>)&#xa0;and&#xa0;high charge transfer resistance (Rct&#xa0;=&#xa0;1.4 kΩ), linked to the&#xa0;bulk crystal morphology&#xa0;limiting active-site exposure. However, the material demonstrates exceptional&#xa0;long-term stability&#xa0;(&gt;&#xa0;10&#xa0;h), highlighting the trade-off between catalytic efficiency and durability imposed by its rigid monoclinic structure. These findings establish a&#xa0;structure–property relationship&#xa0;in CdWO<sub>4</sub>, where the dense, octahedrally coordinated wolframite lattice ensures stability but restricts charge transfer and H⁺ adsorption kinetics.</p> Graphical Abstract <p></p>

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Temperature-Dependent Raman Spectroscopy, First-Principles Analysis, and Hydrogen Evolution in CdWO4 Crystals

  • 期刊论文

  • 发表日期：

    2025年8月2日

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  • D. S. Luz,
  • L. F. Lobato,
  • F. G. S. Oliveira,
  • R. F. Jucá,
  • V. O. Sousa Neto,
  • A. J. Ramiro de Castro,
  • F. F. de Sousa,
  • W. Paraguassu,
  • G. D. Saraiva

摘要

This research reports the temperature-dependent vibrational properties of cadmium tungstate (CdWO4) in its monoclinic structure using Raman spectroscopy. The density functional theory was employed to calculate the Raman mode assignments, band structure, and partial/projected density of states for the crystal. Experimental Raman spectroscopy measurements were conducted across a temperature range of 10–1000 K, revealing that the CdWO4 crystal maintains structural stability throughout this range. Principal component analysis and hierarchical cluster analysis were utilized to evaluate temperature ranges conducive to conformational changes, confirming the absence of phase transitions within the studied conditions. Additionally, the CdWO4 crystal was explored as an electrocatalyst for the hydrogen evolution reaction. As an electrocatalyst, CdWO4 exhibits an overpotential of 870 mV (at 10 mA cm⁻2) and a Tafel slope of 221 mV dec⁻1. The moderate HER activity is attributed to the low electrochemical surface area (ECSA = 1.34 cm2) and high charge transfer resistance (Rct = 1.4 kΩ), linked to the bulk crystal morphology limiting active-site exposure. However, the material demonstrates exceptional long-term stability (> 10 h), highlighting the trade-off between catalytic efficiency and durability imposed by its rigid monoclinic structure. These findings establish a structure–property relationship in CdWO4, where the dense, octahedrally coordinated wolframite lattice ensures stability but restricts charge transfer and H⁺ adsorption kinetics.

Graphical Abstract