Density Functional Theory Study of the Capture and Release of Carbon Dioxide by Benzyl-Disulfide, -Diselenide, and...

Rising levels of CO₂ concentration in our atmosphere and its contribution to climate change are one of the greatest issues our planet is facing. Past experimental work has shown the ability of benzyl-disulfide to reversibly bind CO₂. In the present work, the ability of benzyl-diselenide and benzyl-ditelluride to reversibly bind CO₂ was compared to that of benzyl-disulfide using a density functional theory approach. The effect of solvent polarity on the thermodynamics of CO₂ capture was also investigated. From the results it was found that benzyl-ditelluride offered the most thermoneutral pathway for CO₂ capture and release, whereas benzyl-disulfide offered the least thermoneutral pathway for CO₂ capture. Such thermoneutrality between steps has been stated to be an important property of carbon capture and storage (CCS) technologies. Regarding the various steps involved in CO₂ capture, it was found at the present level of theory that after reduction of the benzyl-dichalcogenide compounds, the formed BnX^- compounds bind to CO₂ via a barrierless process and are therefore expected to efficiently capture CO₂. Moreover, given the similar structural and electronic changes during the electron transfer steps, the kinetics of the electron transfer steps are expected to be similar among the compounds investigated. Thus, the results presented herein suggest that BnTe-TeBn and BnSe-SeBn should be investigated for potential use as CCS technologies.