Correlating the structure of quinone-functionalized carbons with electrochemical CO2 capture performance

Abstract

Electrochemical carbon dioxide capture is emerging as an energy-efficient alternative to traditional carbon capture technology. In particular, redox-active molecules that can capture carbon dioxide when electrochemically reduced and release carbon dioxide when electrochemically re-oxidized are under active development. To prepare a carbon capture device, these molecules can be incorporated into a solid electrode in a battery-like cell. In this work, we explore the scope of a recently developed method where anthraquinones are covalently attached to porous carbon supports to obtain electrodes for electrochemical carbon dioxide capture. We functionalize four different porous carbon materials with varying porosities and surface chemistries, and use gas sorption analysis and solid-state NMR spectroscopy to probe the location of the grafted anthraquinones. All four functionalized materials show electrochemically mediated capture and release of carbon dioxide, and we explore the factors that determine their performance. While the anthraquinone-functionalized mesoporous carbon, f-CMK-3, showed the highest quinone loading, it showed poor quinone utilization for CO 2 capture and poor long-term cycling stability. In contrast, the predominantly microporous functionalized carbon, f-YP-80F, showed a higher quinone utilization and improved cycling stability. This work can guide the design of functionalized carbon electrodes for electrochemical carbon dioxide capture. • A series of four anthraquinone-functionalized porous carbons are prepared. • Quinone grafting is characterised by gas sorption, electrochemistry, solid-state NMR. • All the synthesised materials show electrochemical carbon dioxide capture. • The structural factors determining capture performance are explored. • Quinone grafting sites impact cycle lifetime for electrochemical CO 2 capture.

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