Evaluation of CO(2) and H(2)O Adsorption on a Porous Polymer Using DFT and In Situ DRIFT Spectroscopy

[Image: see text] Numerous hyper-cross-linked polymers (HCPs) have been developed as CO(2) adsorbents and photocatalysts. Yet, little is known of the CO(2) and H(2)O 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 CO(2) and H(2)O adsorption sites on a triazine–biphenyl HCP. We found that CO(2) and H(2)O adsorb on the same HCP sites albeit with different adsorption strengths. The primary amines of the triazines were identified as favoring strong CO(2) binding interactions. Given the potential use of HCPs for CO(2) photoreduction, we also investigated CO(2) and H(2)O adsorption under transient light irradiation. Under irradiation, we observed partial CO(2) and H(2)O desorption and a redistribution of interactions between the H(2)O and CO(2) molecules that remain adsorbed at HCP adsorption sites.