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Structural evolution of CO2-filled pure silica LTA zeolite under high-pressure high-temperature conditions

DOI: 10.1021/acs.chemmater.7b01158 DOI Help

Authors: David Santamaria Perez (Universidad de Valencia) , Tomas Marqueño (Universidad de Valencia) , Simon Macleod (Atomic Weapons Establishment; Imperial College London) , Javier Ruiz-fuertes (Universidad de Valencia) , Dominik Daisenberger (Diamond Light Source) , Raquel Chulia-jordan (Universidad de Valencia) , Daniel Errandonea (Universidad de Valencia) , Jose Luis Jorda (Instituto de Tecnología Química, Universitat Politècnica de València – Consejo Superior de Investigaciones Científicas) , Fernando Rey (Instituto de Tecnología Química, Universitat Politècnica de València – Consejo Superior de Investigaciones Científicas) , Chris Mcguire (University of California Los Angeles) , Adam Makhluf (University of California Los Angeles) , Abby Kavner (University of California Los Angeles) , Catalin Popescu (ALBA-CELLS)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemistry Of Materials

State: Published (Approved)
Published: May 2017

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 α-cages and 1 in the β-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~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.

Subject Areas: Chemistry

Facility: Advanced Photon Source