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.