Cooperative carbon capture and steam regeneration with tetraamine-appended metal-organic frameworks.

Kim, Eugene J; Siegelman, Rebecca L; Jiang, Henry Z H; Forse, Alexander C; Lee, Jung-Hoon; Martell, Jeffrey D; Milner, Phillip J; Falkowski, Joseph M et al. · Science · 2020

basic_science · Level V

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Abstract

Natural gas has become the dominant source of electricity in the United States, and technologies capable of efficiently removing carbon dioxide (CO<sub>2</sub>) from the flue emissions of natural gas-fired power plants could reduce their carbon intensity. However, given the low partial pressure of CO<sub>2</sub> in the flue stream, separation of CO<sub>2</sub> is particularly challenging. Taking inspiration from the crystal structures of diamine-appended metal-organic frameworks exhibiting two-step cooperative CO<sub>2</sub> adsorption, we report a family of robust tetraamine-functionalized frameworks that retain cooperativity, leading to the potential for exceptional efficiency in capturing CO<sub>2</sub> under the extreme conditions relevant to natural gas flue emissions. The ordered, multimetal coordination of the tetraamines imparts the materials with extraordinary stability to adsorption-desorption cycling with simulated humid flue gas and enables regeneration using low-temperature steam in lieu of costly pressure or temperature swings.