Chen Fuqiang, Ding Jiaqi, Guo Kaiqing, Yang Liu, Zhang Zhiguo, Yang Qiwei, Yang Yiwen, Bao Zongbi, He Yi, Ren Qilong
Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, 310027, P. R. China.
Institute of Zhejiang University-Quzhou, 78 Jiuhua Boulevard North, Quzhou, 324000, P. R. China.
Angew Chem Int Ed Engl. 2021 Feb 1;60(5):2431-2438. doi: 10.1002/anie.202011778. Epub 2020 Dec 1.
Separation of Xe and Kr is one of the greatest challenges in the gas industries owing to their close molecular structure and similar properties. Energy-effective adsorption-based separation using chemically stable carbon adsorbents is a promising technology. We propose a strategy for Xe/Kr separation using MOF-derived metallic carbon adsorbents. M-Gallate (M=Ni, Co) were used as precursors to fabricate CoNi alloy nanoparticles embedded carbon adsorbents by one-step auto-reduction pyrolysis. The optimal NiCo@C-700 exhibits record-high IAST selectivity (24.1) and Henry's selectivity (20.1) of Xe/Kr among reported carbon adsorbents. DFT calculations, local density of states calculation, charge density difference, and Bader charge analysis reveal the great affinity with Xe benefits from the presence of Ni or CoNi nanoparticles as a result of more charge transfer from Xe than Kr to metal, thus providing higher binding energy. Breakthrough experiments further verify NiCo@C-700 a promising candidate for Xe/Kr separation.
由于Xe和Kr分子结构相近且性质相似，它们的分离是气体工业面临的最大挑战之一。使用化学性质稳定的碳吸附剂进行基于吸附的高效节能分离是一项很有前景的技术。我们提出了一种使用金属有机框架（MOF）衍生的金属碳吸附剂进行Xe/Kr分离的策略。以M-没食子酸盐（M = Ni、Co）为前驱体，通过一步自还原热解制备了嵌入碳吸附剂中的CoNi合金纳米颗粒。在已报道的碳吸附剂中，最佳的NiCo@C-700对Xe/Kr表现出创纪录的高理想吸附溶液理论（IAST）选择性（24.1）和亨利选择性（20.1）。密度泛函理论（DFT）计算、态密度局部计算、电荷密度差和巴德电荷分析表明，由于Xe向金属的电荷转移比Kr多，Ni或CoNi纳米颗粒的存在使得对Xe具有很强的亲和力，从而提供了更高的结合能。突破实验进一步证实了NiCo@C-700是Xe/Kr分离的一个有潜力的候选材料。
