Electrosynthesis of amino acids from NO and α-keto acids using two decoupled flow reactors

Amino acids have wide application in the food and pharmaceutical industries. Current biotic and chemical syntheses suffer from low efficiency, complex purification operations and high energy consumption. Here we report a sustainable electrocatalytic synthesis of alanine from NO and pyruvic acid over oxide-derived Ag with low-coordination sites under ambient conditions. Mechanistic studies reveal a cascade NO → NH 2 OH → pyruvate oxime → alanine pathway. The quick pyruvate oxime formation and slow pyruvate oxime reduction steps cause various side reactions, leading to low alanine production. Then, a spatially decoupled two-pot electrosynthesis system using flow reactors loaded with oxide-derived Ag is designed for pyruvate oxime formation and reduction reactions. This decoupled system delivers 3.85 g of easily purified alanine with a total Faradaic efficiency of 70% and a purity of >98% at 100 mA cm −2 . Further techno-economic analysis demonstrates the potential. This method is suitable for solar-energy-driven alanine electrosynthesis from polylactic acid wastes and for the fabrication of other amino acids.