Borophene as a Promising Material for Charge-Modulated Switchable CO₂ Capture

Ideal carbon dioxide (CO₂) capture materials for practical applications should bind CO₂ molecules neither too weakly to limit good loading kinetics nor too strongly to limit facile release. Although charge-modulated switchable CO₂ capture has been proposed to be a controllable, highly selective, and reversible CO₂ capture strategy, the development of a practical gas-adsorbent material remains a great challenge. In this study, by means of density functional theory (DFT) calculations, we have examined the possibility of conductive borophene nanosheets as promising sorbent materials for charge-modulated switchable CO₂ capture. Our results reveal that the binding strength of CO₂ molecules on negatively charged borophene can be significantly enhanced by injecting extra electrons into the adsorbent. At saturation CO₂ capture coverage, the negatively charged borophene achieves CO₂ capture capacities up to 6.73 × 10¹⁴ cm^-2. In contrast to the other CO₂ capture methods, the CO₂ capture/release processes on negatively charged borophene are reversible with fast kinetics and can be easily controlled via switching on/off the charges carried by borophene nanosheets. Moreover, these negatively charged borophene nanosheets are highly selective for separating CO₂ from mixtures with CH₄, H₂, and/or N₂. This theoretical exploration will provide helpful guidance for identifying experimentally feasible, controllable, highly selective, and high-capacity CO₂ capture materials with ideal thermodynamics and reversibility.