Villalobos Luis Francisco, Vahdat Mohammad Tohidi, Dakhchoune Mostapha, Nadizadeh Zahra, Mensi Mounir, Oveisi Emad, Campi Davide, Marzari Nicola, Agrawal Kumar Varoon
Laboratory of Advanced Separations (LAS), École Polytechnique Fédérale de Lausanne (EPFL), Sion, Switzerland.
Theory and Simulation of Materials (THEOS) and National Centre for Computational Design and Discovery of Novel Materials (MARVEL), EPFL, Lausanne, Switzerland.
Sci Adv. 2020 Jan 24;6(4):eaay9851. doi: 10.1126/sciadv.aay9851. eCollection 2020 Jan.
Poly(triazine imide) (PTI), a crystalline g-CN, hosting two-dimensional nanoporous structure with an electron density gap of 0.34 nm, is highly promising for high-temperature hydrogen sieving because of its high chemical and thermal robustness. Currently, layered PTI is synthesized in potentially unsafe vacuum ampules in milligram quantities. Here, we demonstrate a scalable and safe ambient pressure synthesis route leading to several grams of layered PTI platelets in a single batch with 70% yield with respect to the precursor. Solvent exfoliation under anhydrous conditions led to single-layer PTI nanosheets evidenced by the observation of triangular g-CN nanopores. Gas permeation studies confirm that PTI nanopores can sieve He and H from larger molecules. Last, high-temperature H sieving from PTI nanosheet-based membranes, prepared by the scalable filter coating technique, is demonstrated with H permeance reaching 1500 gas permeation units, with H/CO, H/N, and H/CH selectivities reaching 10, 50, and 60, respectively, at 250°C.
聚（三嗪酰亚胺）（PTI）是一种晶体石墨相氮化碳，具有二维纳米多孔结构，电子密度间隙为0.34纳米，因其高化学稳定性和热稳定性，在高温氢气筛分方面极具潜力。目前，层状PTI是在潜在不安全的真空安瓿中以毫克量合成的。在此，我们展示了一种可扩展且安全的常压合成路线，单次批量可制备几克层状PTI薄片，相对于前驱体产率为70%。无水条件下的溶剂剥离产生了单层PTI纳米片，通过观察三角形石墨相氮化碳纳米孔得以证明。气体渗透研究证实，PTI纳米孔能够从较大分子中筛分氦气和氢气。最后，通过可扩展的过滤涂层技术制备的基于PTI纳米片的膜在高温下的氢气筛分性能得到了展示，在250°C时氢气渗透率达到1500气体渗透单位，氢气/一氧化碳、氢气/氮气和氢气/甲烷的选择性分别达到10、50和60。
