Scalable Polymeric Few-Nanometer Organosilica Membranes with Hydrothermal Stability for Selective Hydrogen Separation.

Zhu, Lingxiang; Huang, Liang; Venna, Surendar R; Blevins, Adrienne K; Ding, Yifu; Hopkinson, David P; Swihart, Mark T; Lin, Haiqing · ACS Nano · 2021

basic_science · Level V

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Abstract

Nanoporous silica membranes exhibit excellent H<sub>2</sub>/CO<sub>2</sub> separation properties for sustainable H<sub>2</sub> production and CO<sub>2</sub> capture but are prepared via complicated thermal processes above 400 °C, which prevent their scalable production at a low cost. Here, we demonstrate the rapid fabrication (within 2 min) of ultrathin silica-like membranes (∼3 nm) via an oxygen plasma treatment of polydimethylsiloxane-based thin-film composite membranes at 20 °C. The resulting organosilica membranes unexpectedly exhibit H<sub>2</sub> permeance of 280-930 GPU (1 GPU = 3.347 × 10<sup>-10</sup> mol m<sup>-2</sup> s<sup>-1</sup> Pa<sup>-1</sup>) and H<sub>2</sub>/CO<sub>2</sub> selectivity of 93-32 at 200 °C, far surpassing state-of-the-art membranes and Robeson's upper bound for H<sub>2</sub>/CO<sub>2</sub> separation. When challenged with a 3 d simulated syngas test containing water vapor at 200 °C and a 340 d stability test, the membrane shows durable separation performance and excellent hydrothermal stability. The robust H<sub>2</sub>/CO<sub>2</sub> separation properties coupled with excellent scalability demonstrate the great potential of these organosilica membranes for economic H<sub>2</sub> production with minimal carbon emissions.