Graphene-like structure of activated anthracites

Area of Science:

• Materials Science
• Physical Chemistry
• Nanotechnology

Background:

• Activated carbons are widely used porous materials.
• Understanding the atomic structure of activated carbons is key to optimizing their properties.
• Chemical activation of anthracite is a common method for producing activated carbons.

Purpose of the Study:

• To elucidate the detailed atomic structure of activated carbons derived from anthracite.
• To correlate the observed structure with the material's porosity.
• To validate structural models using experimental data.

Main Methods:

• Wide-angle X-ray scattering (WAXS) for structural analysis.
• Molecular dynamics simulations to model atomic arrangements and defects.
• Raman spectroscopy to confirm structural validity.
• Calculation of pair correlation functions and structure factors.

Main Results:

• Activated carbons exhibit stacked graphite-like layers with paracrystalline ordering and significant defects.
• Defects include Stone-Thrower-Wales, mono-vacancy, and di-vacancy types, leading to non-hexagonal rings.
• Simulated structures closely matched experimental diffraction data in both reciprocal and real space.
• High BET surface areas (1500-3430 m²/g) and small average pore sizes (0.75-1.35 nm) were observed.

Conclusions:

• The proposed paracrystalline models with defects accurately represent the structure of activated carbons from anthracite.
• The defective structure is directly linked to the observed porosity characteristics.
• The study provides a robust understanding of activated carbon structure-property relationships.