An energy-saving system containing ion-exchange or nanoporous materials and carbonate ions is proposed, which is capable of capturing CO₂ from ambient air simply by controlling the amount of water (moisture) in contact with the sorbent. The system binds CO₂ from the air when the surrounding is dry, whereas it desorbs CO₂ when it is wet. A design of such CO₂ sorption and desorption systems is investigated using quantum mechanics simulations and is verified by experiments. Its working mechanism is revealed as the free energy change of the chemical reaction of the carbonate ions and water molecules; the free energy change decreases when the number of water molecules in the materials decreases. The influence of pore size, spacing of cations, and surface hydrophobicity of the sorbents on CO₂ capture efficiency are elucidated. The study sheds light on ways to optimize an efficient direct air capture system and therefore contributes to the development of “negative emission technologies.”

提出了一种包含离子交换或纳米多孔材料和碳酸根离子的节能系统，该系统只需控制与吸附剂接触的水量（水分），即可从环境空气中捕获CO ₂。当周围干燥时，该系统会将空气中的CO ₂结合起来，而当潮湿时，该系统会将CO ₂解吸。这种CO _2的设计吸附和解吸系统使用量子力学模拟进行了研究，并通过实验进行了验证。其工作机理通过碳酸根离子与水分子化学反应的自由能变化来揭示。当材料中水分子的数量减少时，自由能的变化减少。阐明了孔径，阳离子间距和吸附剂的表面疏水性对CO ₂捕集效率的影响。该研究为优化高效的直接空气捕获系统提供了方法，从而为“负排放技术”的发展做出了贡献。