Carbon Dioxide Capture in a Carbonate-Pillared Ultramicroporous Metal-Organic Framework

Metal-organic frameworks (MOFs) have emerged as promising candidates for carbon dioxide (CO2) capture due to their ability to tailor pore structures and textural properties with ease. Nevertheless, utilizing low-cost and environmentally benign chemicals as ligand sources is crucial to ensure the sustainable application of MOFs. Herein, we report that Zn-2(atz)(2)(CO3) (atz = 3-amino-1,2,4-triazolate), a carbonated-pillared ultramicroporous MOF that can be synthesized using sodium bicarbonate (also known as "baking soda"), exhibits good CO2 adsorption capacity, achieving 1.9 mmol g(-1) at 298 K and 15 kPa. Furthermore, it displays a moderate isosteric heat of adsorption (Q(st)) for CO2, measuring 37.5 kJ mol(-1) at near-zero coverage, with an exceptional ideal adsorbed solution theory (IAST) CO2/N-2 selectivity of 188 for a 15/85 (v/v) CO2/N-2 mixture at 298 K and 100 kPa. Remarkably, our breakthrough experiments under both dry and humid conditions reveal that Zn-2(atz)(2)(CO3) maintains its CO2 capture capabilities, even at intermediate relative humidity levels (e.g., 40%). Intriguingly, Monte Carlo and dispersion-corrected density functional theory simulations suggest that carbonate anions, by which zinc-aminotriazolate layers are pillared, significantly interact with the CO2 molecules.