Hierarchically porous and single Zn atom-embedded carbon molecular sieves for H<sub>2</sub> separations.

Hu, Leiqing; Lee, Won-Il; Roy, Soumyabrata; Subramanian, Ashwanth; Kisslinger, Kim; Zhu, Lingxiang; Fan, Shouhong; Hwang, Sooyeon et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Hierarchically porous materials containing sub-nm ultramicropores with molecular sieving abilities and microcavities with high gas diffusivity may realize energy-efficient membranes for gas separations. However, rationally designing and constructing such pores into large-area membranes enabling efficient H<sub>2</sub> separations remains challenging. Here, we report the synthesis and utilization of hybrid carbon molecular sieve membranes with well-controlled nano- and micro-pores and single zinc atoms and clusters well-dispersed inside the nanopores via the carbonization of supramolecular mixed matrix materials containing amorphous and crystalline zeolitic imidazolate frameworks. Carbonization temperature is used to fine-tune pore sizes, achieving ultrahigh selectivity for H<sub>2</sub>/CO<sub>2</sub> (130), H<sub>2</sub>/CH<sub>4</sub> (2900), H<sub>2</sub>/N<sub>2</sub> (880), and H<sub>2</sub>/C<sub>2</sub>H<sub>6</sub> (7900) with stability against water vapor and physical aging during a continuous 120-h test.