Capturing and converting CO₂ using amino acids as various commercially valuable nano-carbonates

Carbon dioxide (CO₂) is the most significant greenhouse gas and one of the strategies to reduce CO₂ emission is to convert CO₂ into commercially valuable products. Currently, methods that can effectively capture and convert CO₂ into carbonate nanomaterials, which have unique applications in various fields, have rarely been reported, and there are no universal methods that can capture and convert CO₂ into different nano-carbonates. In this study, an innovative two-step strategy based on amino acids was developed to produce multiple different carbonate nanoparticles, including CaCO₃, BaCO₃, and Ag₂CO₃ nanoparticles with diameters of 70 nm, 50 nm, and 7 nm, respectively. Fundamentally important, the nuclear magnetic resonance data clearly demonstrated that it was the amino acids (e.g., glycine) that dictated the formation of carbonate nanoparticles. In the presence of amino acids, a competition in forming nanoparticles and microparticles was observed, and the formation of nanoparticles was proportional to the carbamate formed from CO₂ reacting with amino acids. In the absence of amino acids, carbonate microparticles (~ 2 μm) were formed.