Structural Evolution of CO2-Filled Pure Silica LTA Zeolite under High-Pressure High-Temperature Conditions

David Santamaria-Perez*, Tomas Marqueno, Simon MacLeod, Javier Ruiz-Fuertes, Dominik Daisenberger, Raquel Chulia-Jordan, Daniel Errandonea, Jose Luis Jorda, Fernando Rey, Chris McGuire, Adam Mahkluf, Abby Kavner, Catalin Popescu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The crystal structure of CO2-filled pure-SiO2 LTA zeolite has been studied at high pressures and temperatures using synchrotron-based X-ray powder diffraction. Its structure consists of 13 CO2 guest molecules, 12 of them accommodated in the large alpha-cages and one in the beta-cages, giving a SiO2/CO2 stoichiometric ratio smaller than 2. The structure remains stable under pressure up to 20 GPa with a slight pressure-dependent rhombohedral distortion, indicating that pressure-induced amorphization is prevented by the insertion of guest species in this open framework. The ambient temperature lattice compressibility has been determined. In situ high-pressure resistive-heating experiments up to 750 K allow us to estimate the thermal expansivity at P approximate to 5 GPa. Our data confirm that the insertion of CO2 reverses the negative thermal expansion of the empty zeolite structure. No evidence of any chemical reaction was observed. The possibility of synthesizing a silicon carbonate at high temperatures and higher pressures is discussed in terms of the evolution of C-O and Si-O distances between molecular and framework atoms.

Original languageEnglish
Pages (from-to)4502-4510
Number of pages9
JournalChemistry of Materials
Volume29
Issue number10
Early online date10 May 2017
DOIs
Publication statusPublished - 23 May 2017

Keywords

  • CARBON-DIOXIDE
  • THERMAL-EXPANSION
  • EQUATIONS
  • METALS
  • QUARTZ
  • STATE
  • AU

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