Clay minerals can adsorb large amounts of CO₂ and are present in anthropogenic storage sites for CO₂. Nanoscale functionalization of smectite clay minerals is essential for developing technologies for carbon sequestration based on these materials and for safe-guarding relevant long-term carbon storage sites. We investigate the adsorption mechanisms of CO₂ in dried and hydrated synthetic Ni-exchanged fluorohectorite clay—using a combination of powder X-ray diffraction, Raman spectroscopy, and inelastic neutron scattering. Both dried and hydrated Ni-exchanged fluorohectorite show crystalline swelling and spectroscopic changes in response to CO₂ exposure. These changes can be attributed to interactions with [Ni(OH)_0.83(H₂O)_1.17]_0.37^1.17+-interlayer species, and swelling occurs solely in the interlayers where this condensed species is present. The experimental conclusions are supported by density functional theory simulations. This work demonstrates a hitherto overlooked important mechanism, where a hydrogenous species present in the nanospace of a clay mineral creates sorption sites for CO₂.

中文翻译：

---

氢氧化镍在合成粘土矿物的纳米空间中层间捕获CO ₂的能力

粘土矿物可以吸收大量的CO ₂，并且存在于人为的CO ₂储存位。蒙脱石粘土矿物的纳米级功能化对于开发基于这些材料的碳固存技术以及安全保护相关的长期碳存储场所至关重要。我们结合粉末X射线衍射，拉曼光谱和非弹性中子散射研究了干燥和水合的合成镍交换氟锂蒙脱石粘土中CO ₂的吸附机理。干燥和水合的镍交换氟锂蒙脱石均显示出晶体溶胀和响应于CO ₂暴露的光谱变化。这些变化可归因于与[Ni（OH）_0.83的相互作用（H ₂ O）_1.17 ]]> _{0.37 1.17} ^+-中间层物质，并且溶胀仅发生在存在该冷凝物的中间层中。实验结论得到密度泛函理论仿真的支持。这项工作证明了迄今为止被忽视的重要机制，其中粘土矿物的纳米空间中存在的氢物种产生了CO _2的吸附位。