Versatile Amino Acid Synthesis from Ambient Air and α‑Keto Acids via Tandem Plasma‑Electrocatalysis

Amino acids serve a crucial role in the chemical and biological sciences. However, conventional biotic and chemical synthesis strategies typically require harsh conditions and suffer from low efficiency. Here we report a tandem plasma-electrocatalytic approach for amino acid synthesis from α-keto acid and ambient air. Using alanine as a representative example, this integrated process begins with plasma-discharge activation of air, which produces nitrate at a rate of 5.28 mmol h^-1. Subsequently, a bimetallic AgBi catalyst facilitates the co‑electrolysis of nitrate and pyruvic acid, yielding alanine with a Faradaic efficiency of 58% at -200 mA cm^-2 and an overall yield of 62.6%. In this step, Bi sites drive the nitrate-to-hydroxylamine conversion, while the Ag-Bi interface catalyzes the reduction of the resulting pyruvic acid oxime, which is formed spontaneously from pyruvic acid and hydroxylamine, into the final alanine product. Moreover, our tandem system can be extended to synthesize other α-amino acids, including aspartic acid, 2-aminobutyric acid, glycine, and leucine, indicating its high versatility. Further techno-economic analysis confirms the substantial market potential of this strategy.