Three-Step Streamlined Synthesis of Glycine from Carbon Dioxide Using Benign Catalysts in Water

Abstract Amino acids are essential feedstocks with large-scale industrial demand; however, their production is dominated by fermentation and petrochemical production routes requiring energy-intensive operations and extensive separations. Therefore, developing alternative routes from renewable feedstocks that reduce process energy intensity is important for sustainable manufacturing. Here, we report a three-step aqueous process for synthesizing glycine from gaseous carbon dioxide (CO2) and nitrate—both obtainable from air—using benign catalysts and without intermediate purification steps. CO2 was electrochemically reduced to potassium formate (step 1), thermally coupled to potassium oxalate (step 2), and converted to glycine via electrocatalytic C–N bond formation with nitrate (step 3). Under optimized conditions, the integrated electrochemical steps achieved peak faradaic efficiencies of 43% (step 1) and 51% (step 3), while the formate-to-oxalate coupling (step 2) proceeded in 90% yield. The process employed water as the only processing solvent (avoiding organic solvents and demonstrating compatibility with wet CO2 streams), used non-toxic indium and bismuth-nanoparticle electrocatalysts, and generated hydroxylamine in situ. This work demonstrates an integrated and environmentally compatible pathway for amino acid synthesis from feedstocks obtainable from air and highlights the potential of modular electrosynthetic platforms for sustainable chemical manufacturing.