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

verfasst von

Mario Evers, Karin Hauser, Wolfgang G. Hinze, Nele Klinkenberg, Yasar Krysiak, Daniel Mombers, Sebastian Polarz

Abstract

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.

Organisationseinheit(en)

Institut für Anorganische Chemie

Externe Organisation(en)

Universität Konstanz

Typ

Artikel

Journal

Journal of Materials Chemistry A

Band

12

Seiten

11332-11343

Anzahl der Seiten

12

ISSN

2050-7488

Publikationsdatum

21.05.2024

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Chemie (insg.), Erneuerbare Energien, Nachhaltigkeit und Umwelt, Werkstoffwissenschaften (insg.)

Ziele für nachhaltige Entwicklung

SDG 7 – Erschwingliche und saubere Energie

Elektronische Version(en)

https://doi.org/10.1039/d4ta01381f (Zugang: Offen)