CO2 Capture via Crystalline Hydrogen-Bonded Bicarbonate Dimers

Human activities in the last one and a half centuries have perturbed the natural carbon cycle, shifting massive amounts of carbon from the geosphere into the atmosphere and leading to climate change at an unprecedented pace. Carbon capture and storage, consisting of capturing CO₂ from fossil fuel emissions and sequestering it deep underground, offer the prospect of limiting the increase in the atmospheric CO₂ concentration and the global temperature. This requires the development and large-scale deployment of energy-efficient carbon-capture technologies. Here, we demonstrate a promising approach to CO₂ capture based on crystallization of bicarbonate-water clusters with a simple guanidine compound. The CO₂ separation cycle involves a unique proton-transfer mechanism via the formation of a carbonic acid dimer, leading to efficient CO₂ release and quantitative regeneration of the guanidine compound and requiring significantly less energy than state-of-the-art carbon-capture technologies.