Temperature controlled swelling of graphene oxide for switchable dehumidification membranesстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 15 февраля 2024 г.
Аннотация:Variation of water permeance and interlayer spacing of graphene oxide (GO) is traced with in-situ X-ray diffraction upon its heating/cooling in dry (∼1000 Pa), humid (∼100 % RH) air and liquid water. Reversible variation of GO interlayer distance ranging 8.3-7.2 Å in dry air, 11-7.5 Å in humid air and 13.9-12.4 Å in liquid water is revealed in the temperature range of 25–80 °C. Accounting for GO layer thickness of ∼6 Å it corresponds manifold alterations of slit width with temperature and water vapor pressure, resulting in over 3 orders of magnitude variation of membrane performance. A typical rise of the permeance of 300–500 % within the temperature range at constant humidity is contraposed to a miserable increase in the activation energy for H2O transport, revealing the decisive impact of slit sizes on GO performance. The effect is addressed to entropy-driven variation of water absorption heat with slit sizes in GO. Variation of interlayer spacing of ∼10 % was also exposed with thermal dissociation of GO groups and H+ migration to the interlayer space as supported by semi-empirical calculations. Reversible structural changes in GO are successfully exploited for fabrication thermally switched membranes for dehumidification with initial permeance of ∼1.1·10−6 mol m−2 Pa−1·s−1 and its variation over 50 % at supplied power of ∼500 W/m2.