Site-Specific CO₂ Adsorption and Zero Thermal Expansion in an Anisotropic Pore Network

Detailed neutron powder diffraction (NPD) experiments were carried out on the parent and CO 2 adsorbed Mg-MOF-74 (MOF: metal–organic framework). Data collected at low temperature revealed two CO 2 adsorption sites on the pore surface and multiple changes in the framework as a function of CO 2 loading. Upon heating the samples to room temperature, the data revealed minimal changes in expansivity upon adsorption of up to 0.94 CO 2 /Mg (≈ 25% mass fraction). Further, temperature-dependent data collected on the bare framework reveals net zero thermal expansion between 10 and 475 K.