Methane clathrate hydrate (MCH) is a promising energy resource, but controllable extraction of CH 4 from MCH remains a challenge. Gradually replacing CH 4 in MCH with CO 2 is an attractive scheme, as it is cost efficient and mitigates the environmentally harmful effects of CO 2 by sequestration. However, the practicable implementation of this method has not yet been achieved. In this study, using in situ neutron diffraction, we confirm that CH 4 in the 5 12 6 2 cages of bulk structure-I (sI) MCH can be substituted by gaseous CO 2 under high pressure and low temperature with a high substitution ratio (∼44%) while conserving the structure of the hydrate framework. First-principles calculations indicate that CO 2 binds more strongly to the 5 12 6 2 cages than methane does, and that the diffusion barri...

中文翻译：

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CO 2萃取CH 4气体：通过双分子迭代法代替包合物水合物

甲烷包合物水合物（MCH）是一种有前途的能源，但是可控地从MCH提取CH 4仍然是一个挑战。用CO 2逐渐取代MCH中的CH 4是一种有吸引力的方案，因为它具有成本效益，并通过隔离减少了CO 2对环境的不利影响。但是，尚未实现该方法的实际实现。在这项研究中，我们使用原位中子衍射法确定了在大体积结构-I（sI）MCH的5 12 6 2个笼中的CH 4可以在高压和低温下以高取代率被气态CO 2取代（约44％），同时保留了水合物骨架的结构。第一性原理计算表明，与甲烷相比，CO 2与5 12 6 2笼的结合更牢固，并且扩散障碍...