Evaluation of CO2 and H2O Adsorption on a Porous Polymer Using DFT and In Situ DRIFT Spectroscopy

Giulia E M Schukraft; Ioanna Itskou; Robert T Woodward; Bart Van Der Linden; Camille Petit; Atsushi Urakawa

doi:10.1021/acs.jpcb.2c03912

Evaluation of CO₂ and H₂O Adsorption on a Porous Polymer Using DFT and In Situ DRIFT Spectroscopy

J Phys Chem B. 2022 Oct 13;126(40):8048-8057. doi: 10.1021/acs.jpcb.2c03912. Epub 2022 Sep 28.

Authors

Giulia E M Schukraft¹, Ioanna Itskou¹, Robert T Woodward², Bart Van Der Linden³, Camille Petit¹, Atsushi Urakawa³

Affiliations

¹ Barrer Centre, Department of Chemical Engineering, South Kensington Campus, Imperial College London, London SW7 2AZ, U.K.
² Institute of Materials Chemistry and Research, Faculty of Chemistry, University of Vienna, Währinger Straße 42, 1090 Vienna, Austria.
³ Catalysis Engineering, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.

Abstract

Numerous hyper-cross-linked polymers (HCPs) have been developed as CO₂ adsorbents and photocatalysts. Yet, little is known of the CO₂ and H₂O adsorption mechanisms on amorphous porous polymers. Gaining a better understanding of these mechanisms and determining the adsorption sites are key to the rational design of improved adsorbents and photocatalysts. Herein, we present a unique approach that combines density functional theory (DFT), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and multivariate spectral analysis to investigate CO₂ and H₂O adsorption sites on a triazine-biphenyl HCP. We found that CO₂ and H₂O adsorb on the same HCP sites albeit with different adsorption strengths. The primary amines of the triazines were identified as favoring strong CO₂ binding interactions. Given the potential use of HCPs for CO₂ photoreduction, we also investigated CO₂ and H₂O adsorption under transient light irradiation. Under irradiation, we observed partial CO₂ and H₂O desorption and a redistribution of interactions between the H₂O and CO₂ molecules that remain adsorbed at HCP adsorption sites.