• Menart, Martin J.
• Mccue, Alan J.
• Ciobanu, Cristian V.
• Anderson, James A.
• Vega-Maza, David
• Ngo, Chilan
• Richards, Ryan M.
• Shulda, Sarah
• Mutch, Greg A.

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. <br/>

Topics

• impedance spectroscopy
• surface
• Carbon
• activation
• sintering