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.