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Alanine is widely employed for synthesizing polymers, pharmaceuticals, and agrochemicals. Electrocatalytic coupling of biomass molecules and waste nitrate is attractive for the nitrate removal and alanine production under ambient conditions. However, the reaction efficiency is relatively low due to the activation of the stable substrates, and the coupling of two reactive intermediates remains challenging. Herein, we realize the integrated tandem electrochemical‐chemical‐electochemical synthesis of alanine from the biomass‐derived pyruvic acid (PA) and waste nitrate (NO3−) catalyzed by PdCu nano‐bead‐wires (PdCu NBWs). The overall reaction pathway is demonstrated as a multiple‐step catalytic cascade process via coupling the reactive intermediates NH2OH and PA on the catalyst surface. Interestingly, in this integrated tandem electrochemical‐chemical‐electrochemical catalytic cascade process, Cu facilitates the electrochemical reduction of nitrate to NH2OH intermediates, which chemically couple with PA to form the pyruvic oxime, and Pd promotes the electrochemical reduction of pyruvic oxime to the desirable alanine. This work provides a green strategy to convert waste NO3− to wealth and enriches the substrate scope of renewable biomass feedstocks to produce high‐value amino acids. [ABSTRACT FROM AUTHOR]

Thedensity of glycine, l-alanine, and l-serinein formamide–water mixtures was measured at 298.15 K and usedto calculate the apparent molar volume Vϕand limiting partial molar volume Vϕ° of the amino acids. Transfer partial molar volume ΔtrVϕ° from water toformamide–water mixtures and the volumetric interaction coefficientswere also obtained to interpret the solute–solvent interaction.Values of ΔtrVϕ° of the three amino acids were all positive and increased withincreasing formamide concentration in the mixtures, in the order of l-alanine < glycine < l-serine, which was consistentwith the cosphere overlap model. The interaction of formamide moleculesdecreased its structural-breaking effect and consequent interactionwith amino acids, leading to negative triplet interaction coefficients. [ABSTRACT FROM AUTHOR]