supporting information from Flue-gas and direct-air capture of CO<sub>2</sub> by porous metal-organic materials

Sequestration of CO<sub>2</sub>, either from gas mixtures or directly from air (direct air capture), is a technological goal important to large-scale industrial processes such as gas purification and the mitigation of carbon emissions. Previously, we investigated five porous materials, three porous metal-organic materials (MOMs), a benchmark inorganic material, <b>Zeolite 13X</b> and a chemisorbent, <b>TEPA-SBA-15</b>, for their ability to adsorb CO<sub>2</sub> directly from air and from simulated flue gas. In this contribution, a further 10 physisorbent materials that exhibit strong interactions with CO<sub>2</sub> have been evaluated by temperature-programmed desorption for their potential utility in carbon capture applications: four hybrid ultramicroporous materials, <b>SIFSIX-3-Cu</b>, <b>DICRO-3-Ni-i</b>, <b>SIFSIX-2-Cu-i</b> and <b>MOOFOUR-1-Ni</b>; five microporous MOMs, <b>DMOF-1</b>, <b>ZIF-8</b>, <b>MIL-101</b>, <b>UiO-66</b> and <b>UiO-66-NH<sub>2</sub></b>; an ultramicroporous MOM, <b>Ni-4-PyC</b>. The performance of these MOMs was found to be negatively impacted by moisture. Overall, we demonstrate that the incorporation of strong electrostatics from inorganic moieties combined with ultramicropores offers improved CO<sub>2</sub> capture performance from even moist gas mixtures but not enough to compete with chemisorbents.