Xu Yuan-Zi, Abbott Daniel F, Poon Lok Nga, Mougel Victor
Department of Chemistry and Applied Biosciences, ETH Zürich Vladimir-Prelog-Weg 1-5 8093 Zürich Switzerland
EES Catal. 2025 Mar 31. doi: 10.1039/d5ey00016e.
This study presents a facile tandem strategy for improving the efficiency of glycine electrosynthesis from oxalic acid and nitrate. In this tandem electrocatalytic process, oxalic acid is first reduced to glyoxylic acid, while nitrate is reduced to hydroxylamine. Subsequent coupling of these two precursors results in the formation of a C-N bond, producing the intermediate glyoxylic acid oxime, which is further reduced to glycine. Here we show, using only a simple Pb foil electrode, which maximizes the yield of the first step of the transformation ( the reduction of oxalic acid to glyoxylic acid) prior to the coupling step allows for an unprecedented selectivity and conversion for glycine electrosynthesis to be achieved. Overall, a maximum glycine faradaic efficiency (FE) of 59% is achieved at -300 mA cm and a high glycine partial current density of -232 mA cm and a glycine production rate of 0.82 mmol h cm are attained at -400 mA cm, thereby paving the way for an energy and economically efficient electrochemical synthesis of glycine.
本研究提出了一种简便的串联策略，用于提高由草酸和硝酸盐电合成甘氨酸的效率。在这种串联电催化过程中，草酸首先被还原为乙醛酸，而硝酸盐被还原为羟胺。这两种前体随后偶联形成C-N键，生成中间体乙醛酸肟，乙醛酸肟进一步还原为甘氨酸。在这里我们展示，仅使用一个简单的铅箔电极，在偶联步骤之前最大化转化第一步（草酸还原为乙醛酸）的产率，能够实现甘氨酸电合成前所未有的选择性和转化率。总体而言，在-300 mA cm²时实现了59%的最大甘氨酸法拉第效率（FE），在-400 mA cm²时获得了-232 mA cm²的高甘氨酸分电流密度和0.82 mmol h⁻¹ cm⁻²的甘氨酸产率，从而为能量和经济高效的甘氨酸电化学合成铺平了道路。
