Oriented Synthesis of Glycine from CO2, N2, and H2O via a Cascade Process

Abstract

Air contains carbon, hydrogen, oxygen, and nitrogen elements that are essential for the constitution of amino acids. Converting the air into amino acids, powered with renewable electricity, provides a green and sustainable alternative to petrochemical-based methods that produce waste and pollution. Here, taking glycine as an example, we demonstrated the complete production chain for electrorefining amino acids directly from CO₂, N₂, and H₂O. Such a prospective Scheme was composed of three modules, linked by a spontaneous C-N bond formation process. The high-purity bridging intermediates, separated from the stepwise synthesis, boosted both the carbon selectivity from CO₂ to glycine of 91.7 % and nitrogen selectivity from N₂ to glycine of 98.7 %. Under the optimum condition, we obtained glycine with a partial current density of 160.8 mA cm^-2. The high-purity solid glycine product was acquired with a separation efficiency of 98.4 %. This work unveils a green and sustainable method for the abiotic creation of amino acids from the air components.

Keywords: CO2 electroreduction; N2 fixation; Sustainable glycine synthesis; full-path design.