Dual Active Sites on Cu/Cu₂O Heterostructures for the Cascade Electrocatalytic Synthesis of Amino Acids

Electrocatalytic C-N coupling enables the efficient and sustainable production of amino acids. However, it suffers from complex reaction pathways and intense adsorption competition between the reactants and intermediates on a single site. Herein, we report a cascade catalytic strategy on Cu/Cu₂O heterostructures for the electrosynthesis of amino acids from nitrate and keto acids. The catalysts are capable of producing a wide range of amino acids (including alanine, glycine, leucine, and glutamic acid), achieving an impressively high Faradaic efficiency of up to 75.78% and a yield of as high as 478.89 mmol h^-1g_cat^-1 for alanine. Mechanism explorations disclose the reconstruction of CuO/C electrocatalysts into Cu/Cu₂O heterostructures and a cascade catalytic pathway on Cu⁰/Cu⁺ dual sites. The reduction of NO₃^- and the protonation of C═N intermediates are successively realized on the Cu⁰ and Cu⁺ sites, respectively. Meanwhile, abundant Cu/Cu₂O interfaces facilitate the transfer of intermediates. This work provides new insights into the design of bimetallic active sites for the electrosynthesis of amino acids and is conducive to the highly efficient and sustainable production of highly value-added organonitrogen compounds.