Abstract
Solid metal oxides for carbon capture exhibit reduced adsorption capacity following high-temperature exposure, due to surface area reduction by sintering. Furthermore, only low-coordinate corner/edge sites on the thermodynamically stable (100) facet display favorable binding toward CO2, providing inherently low capacity. The (111) facet, however, exhibits a high concentration of low-coordinate sites. In this work, MgO(111) nanosheets displayed high capacity for CO2, as well as a ∼65% increase in capacity despite a ∼30% reduction in surface area following sintering (0.77 mmol g–1 @ 227 m2 g–1 vs 1.28 mmol g–1 @ 154 m2 g–1). These results, unique to MgO(111), suggest intrinsic differences in the effects of sintering on basic site retention. Spectroscopic and computational investigations provided a new structure–activity insight: the importance of high-temperature activation to unleash the capacity of the polar (111) facet of MgO. In summary, we present the first example of a faceted sorbent for carbon capture and challenge the assumption that sintering is necessarily a negative process; here we leverage high-temperature conditions for facet-dependent surface activation.
Original language | English |
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Pages (from-to) | 4736-4742 |
Number of pages | 7 |
Journal | Journal of the American Chemical Society |
Volume | 140 |
Issue number | 13 |
Early online date | 19 Mar 2018 |
DOIs | |
Publication status | Published - 4 Apr 2018 |
Bibliographical note
This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) via a Doctoral Training Grant for G.A.M. (EP/K0502960/1) and a Doctoral Prize Fellowship (EP/M50791X/1). Dedicated to the memory of Kenneth J. Klabunde.Supporting Information. Synthesis procedure, experimental methods, computational methods, transmission microscopy images, N2 adsorption-desorption isotherms and pore size distributions, additional CO2 adsorption isotherms and density functional theory model surfaces. This material is available free of charge via the Internet at http://pubs.acs.org.