Potassium Nickel hexacyanoferrate Prussian Blue Analogues (K-NiFe-PBAs) offer an excellent platform for efficient CO₂ capture due to their porous nature and accessible channels. Herein, the effect of Ni:K atomic ratio on the structure and the CO₂ storage capacity was studied by employing K-NiFe-PBAs with Ni:K ratio of ca. 2.5 and 12. The porosity and the isosteric heat of CO₂ adsorption can be modulated and optimized by varying the Ni:K atomic ratio in the PB framework and thus, covering the thermodynamic criterion for easy CO₂capture and release with acceptable energy costs. The synthesized K-NiFe-PBAs containing only trace amounts of K⁺ ions (with Ni:K = 12) shows an adsorption capacity (∼3.0 mmol g^–1 CO₂ at 273 K and 100 kPa) comparable to other well established CO₂ adsorbents. In situ FTIR spectroscopy was further employed to elucidate the host–guest interaction chemistry and the dynamics of K-NiFe-PBAs within CO₂ and H₂O. The analysis enabled, to the best of our knowledge, is the first FTIR spectroscopic observation of the high sensitivity of the material to structural distortions induced by small changes under water vapor pressure. It was found that H₂O hardly affects CO₂ adsorption and the materials are perspective for CO₂ capture in the presence of water.

六氰基铁酸镍钾普鲁士蓝类似物 (K-NiFe-PBA)由于其多孔性质和可进入的通道，为高效的 CO ₂捕获提供了极好的平台。在本文中，通过使用镍：钾比约为 10 的 K-NiFe-PBA 来研究Ni：K 原子比对结构和 CO ₂存储容量的影响。2.5 和 12.可以通过改变 PB 框架中的 Ni:K 原子比来调节和优化CO ₂吸附的孔隙率和等量热，从而涵盖以可接受的能源成本轻松捕获和释放CO ₂的热力学标准。仅含有痕量 K ⁺离子（Ni:K = 12）的合成 K-NiFe- PBA 显示出吸附容量（~3.0 mmol g^–1 CO ₂在 273 K 和 100 kPa) 与其他成熟的 CO ₂吸附剂相当。进一步采用原位FTIR 光谱来阐明 CO ₂和 H ₂ O中 K-NiFe-PBA 的主客体相互作用化学和动力学。据我们所知，该分析是第一次 FTIR 光谱观察材料对水蒸气压力下微小变化引起的结构变形的高度敏感性。发现H ₂ O几乎不影响CO ₂吸附，并且该材料在水存在下可用于CO ₂捕获。