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Publication Citation: Time dependent CO2 sorption hysteresis in a one-dimensional microporous octahedral molecular sieve

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Author(s): Laura Espinal; Winnie K. Wong-Ng; Andrew J. Allen; Daniel W. Siderius; Chad R. Snyder; Eric J. Cockayne; Lan (. Li; James A. Kaduk; Anais E. Espinal; Steven L. Suib; Chun Chiu;
Title: Time dependent CO2 sorption hysteresis in a one-dimensional microporous octahedral molecular sieve
Published: April 06, 2012
Abstract: A critical challenge in the development of novel carbon capture materials with engineered porous architectures is to understand and control the phenomenon of sorption hysteresis, whereby the path to adsorption of gas molecules by the porous host differs from that to desorption. We show that a one-dimensional (1D) microporous octahedral molecular sieve with manganese oxide framework (OMS-2) exhibits time dependent hysteresis behavior at 303 K and up to 25 bar, which persists at temperatures slightly above the critical temperature of bulk CO2 (304.25 K). We hypothesize that the cation inside the pore serves as a gate keeper that only allowing allows CO2 molecules to enter fully into the 1D tunnel-shaped pores via a highly unstable transition state when gas loadings exceed 0.75 mmol of CO2 per g OMS-2. The energy barrier associated with the gate-keeping effect suggests an adsorption mechanism in which kinetic trapping of CO2 is responsible for the observed hysteretic behavior.
Citation: Journal of the American Chemical Society
Volume: 134
Pages: pp. 7944 - 7951
Keywords: mircroporous materials; molecular sieves; CO2 adsorption; carbon capture; gas sorption hysteresis
Research Areas: Ceramics, Structures, Nanomaterials, Composition, Properties