A Novel Aliphatic Zr-Based Nanocluster With S-Shaped Channel for CO2 Adsorption and Separation Under Humid Condition.

Carbon dioxide (CO2) not only contributes to global warming, but also poses challenges in industrial processes, such as the purification of acetylene (C2H4). Herein, a novel aliphatic Zr-based nanocluster, ZJU-527(Zr), was synthesized from low-cost citric acid. It exhibits a specific surface area of 174.24 m2/g, an S-shaped channel (4.52-5.13 Å), and excellent stability over a pH range of 3-12. CO2 adsorption on ZJU-527(Zr) is well maintained after five cycles, owing to its excellent chemical and thermal stability. ZJU-527(Zr) exhibits excellent humidity resistance, with dynamic CO2 adsorption remaining nearly unchanged (7.05 cm3/g at dry and 5.17 cm3/g at 80% RH). For a CO2/N2 (v/v, 15/85) mixture, it has excellent ideal adsorbed solution theory selectivity of 200.60 and dynamic separation coefficients (29.90 at dry, 21.27 at 80% relative humidity (RH)). During Ar purging, CO2 is readily desorbed from the S-shaped channel in both CO2/N2 and CO2/C2H4 systems, due to its low isosteric heat of adsorption (20.64 kJ/mol). Thus, ZJU-527(Zr) is a promising candidate for CO2 adsorption and separation, with easy desorption and effective regeneration.