Organic magnetic nanoparticles catalyze CO₂ capture in hydrogen-bonded nanocages via water-driven crystallization

Limiting global warming increasingly relies on the development of environmentally friendly CO₂ capture strategies. Crystallization is renowned for versatile separation and purification, yet traditional compound crystallization-based CO₂ capture still necessitates intricate preparation processes, stringent reaction conditions, and high regenerative energy consumption. As an ambitious sustainability goal, natural water could be used as a precursor of crystallization to construct hydrogen-bonded water cages for CO₂ capture, but main obstacles are slow crystallization kinetics and low capture capacity. Here, a water-activation-induced crystallization strategy by organic magnetic nanoparticles (Methionine@Fe₃O₄) has been proposed for efficient CO₂ capture. Local water ordering strengthened by hydrophobic amino acids and abundant nucleation sites provided by nanoparticles create hotspots for hydration phase transition and crystal growth, with a CO₂ capture capacity of 118.7 v/v (22.7 wt%). Favorable biocompatibility and stable performance are conducive to the industrial application of this nanomaterial, and the excellent magnetic recyclable property enables simple separation from clean water. This strategy demonstrates an extraordinary CO₂ capture potential compared to state-of-the-art systems, thus providing an inspiration for sustainable CO₂ capture and storage with zero resource depletion (ZRD).