Structure of V(2)O(5)*nH(2)O xerogel solved by the atomic pair distribution function technique

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nanomaterials

Background:

• Vanadium pentoxide (V(2)O(5)) xerogels are important materials with applications in catalysis and energy storage.
• Understanding their local and long-range atomic structure is crucial for optimizing their properties.
• Previous studies have faced challenges in fully elucidating the complex turbostratic structure.

Purpose of the Study:

• To resolve the long-standing ambiguity regarding the local and long-range atomic structure of V(2)O(5)*nH(2)O xerogel.
• To provide a detailed three-dimensional structural model of the xerogel.
• To investigate the stacking and ordering of V(2)O(5) layers.

Main Methods:

• Utilized the atomic pair distribution function (PDF) technique.
• Employed X-ray diffraction (XRD) data analysis.
• Performed structural modeling and refinement.

Main Results:

• Determined the full three-dimensional structure of the lamellar turbostratic V(2)O(5)*nH(2)O xerogel.
• Showed that xerogel slabs consist of bilayered V(2)O(5) layers formed by square pyramidal VO(5) units.
• Identified a monoclinic unit cell (space group C2/m) with specific lattice parameters (a = 11.722(3) Å, b = 3.570(3) Å, c = 11.520(3) Å, β = 88.65°).
• Observed signatures of turbostratic disorder in the stacking sequence, with structural coherence limited to 50 Å.

Conclusions:

• The atomic-scale structure of V(2)O(5)*nH(2)O xerogel is well-described by stacked bilayers of V(2)O(5) layers.
• Water molecules are intercalated between these bilayers.
• The study successfully addresses the long-standing structural questions of V(2)O(5) xerogels, providing a foundation for future research and applications.