The development of inexpensive porous solid sorbents, such as porous carbons, that can selectively capture carbon dioxide (CO₂) from natural gas wells is essential to reduce emission of CO₂ to the atmosphere. However, at higher pressures, the selectivity for CO₂ over that for methane (CH₄) remains poor. Here we show that H₂O can be imbibed within asphalt-derived porous carbon, with a surface area of 4,200 m² g⁻¹, to generate a hydrated powder material. While maintaining a high CO₂ uptake capacity of 48 mmol g⁻¹ (211 wt%), the molar selectivity for CO₂ over CH₄ increases to >200:1 and the H₂O remains within the pores on repeated cycling. To mimic realistic natural gas wells, we used a 90% CH₄ and 10% CO₂ gas mixture and showed selective CO₂ separation at 20 bar. Furthermore, in situ vibrational spectroscopy reveals the formation of an ordered matrix within the pores consisting of gas hydrates.

能够选择性地从天然气井中捕获二氧化碳（CO ₂）的廉价多孔固体吸附剂（例如多孔碳）的开发对于减少向大气中的CO ₂排放至关重要。然而，在较高压力下，CO ₂的选择性比甲烷（CH ₄）的选择性仍然差。在此我们表明，H ₂ O可以被吸入沥青质多孔碳中，表面积为4,200 m ² g ^-1，从而生成水合粉末材料。在保持48 mmol g ^-1（211 wt％）的高CO ₂吸收能力的同时，相对于CH _4而言，CO ₂的摩尔选择性增加到> 200：1，并且在重复循环时H ₂ O保留在孔中。为了模拟现实的天然气井，我们使用了90％的CH ₄和10％的CO ₂气体混合物，并在20 bar下显示了选择性的CO ₂分离。此外，原位振动光谱揭示了在由气体水合物组成的孔内形成有序基质。