TY - JOUR

T1 - Spatial tuning of adsorption enthalpies by exploiting spectator group effects in organosilica carbon capture materials

AU - Evers, Mario

AU - Hauser, Karin

AU - Hinze, Wolfgang G.

AU - Klinkenberg, Nele

AU - Krysiak, Yasar

AU - Mombers, Daniel

AU - Polarz, Sebastian

N1 - Funding Information: This project was funded by a grant from the Deutsche Forschungsgemeinscha (DFG): Grant numbers PO 780/23-1 and HA 5142/6-1. We thank Marvin Tr¨ager, Katharina Rüther and Andreas Schneider for the molecular modelling calculations.

PY - 2024/4/4

Y1 - 2024/4/4

N2 - Functional gradient materials can process more complex tasks than a mixture of their homogeneous analogs. Generating such materials is difficult as it necessitates spatial control over chemical and/or structural properties. A gradient is a unique degree of freedom in hierarchical material architectures, and as such, biology has managed exploiting the full potential of graded structures. For instance, despite being present at a comparably low concentration (approaching 420 ppm in 2023), plants are capable of capturing carbon dioxide from the air. Binding occurs in the carboxysome, a complex entity characterized by pores with engineered surfaces composed of shell proteins that create a concentration gradient of CO2 towards an enzyme responsible for the first conversion step. The current paper hypothesizes that porous organosilica materials can mimic some of the features of the mentioned biological paragon. Primary amines as sites for interacting with CO2 are surrounded by spectator groups on bifunctional surfaces. It is found that the proper choice of the spectator group almost doubles the adsorption enthalpy. Above a critical density, the hydrophobic moieties create a quasi-solvent layer on the surfaces in which CO2 molecules dissolve. When the density of the spectator groups gradually changes inside a graded organosilica monolith, one obtains zones varying systematically in adsorption enthalpy. Directionality in affinity towards CO2 and controlled transport properties are realized.

AB - Functional gradient materials can process more complex tasks than a mixture of their homogeneous analogs. Generating such materials is difficult as it necessitates spatial control over chemical and/or structural properties. A gradient is a unique degree of freedom in hierarchical material architectures, and as such, biology has managed exploiting the full potential of graded structures. For instance, despite being present at a comparably low concentration (approaching 420 ppm in 2023), plants are capable of capturing carbon dioxide from the air. Binding occurs in the carboxysome, a complex entity characterized by pores with engineered surfaces composed of shell proteins that create a concentration gradient of CO2 towards an enzyme responsible for the first conversion step. The current paper hypothesizes that porous organosilica materials can mimic some of the features of the mentioned biological paragon. Primary amines as sites for interacting with CO2 are surrounded by spectator groups on bifunctional surfaces. It is found that the proper choice of the spectator group almost doubles the adsorption enthalpy. Above a critical density, the hydrophobic moieties create a quasi-solvent layer on the surfaces in which CO2 molecules dissolve. When the density of the spectator groups gradually changes inside a graded organosilica monolith, one obtains zones varying systematically in adsorption enthalpy. Directionality in affinity towards CO2 and controlled transport properties are realized.

UR - http://www.scopus.com/inward/record.url?scp=85190729208&partnerID=8YFLogxK

U2 - 10.1039/d4ta01381f

DO - 10.1039/d4ta01381f

M3 - Article

AN - SCOPUS:85190729208

JO - Journal of Materials Chemistry A

JF - Journal of Materials Chemistry A

SN - 2050-7488

ER -