α-Amino acids (α-aa) play a significant role in pharmaceutical and chemical industries. Here, we reported an electrochemical tandem system that couples the anodic dehydrogenation of amines and the cathodic carboxylation of imines. Based on a designed Lewis acid (LA)-enriched CeO₂ with indium (denoted as In-CeO_x) as cathodic electrocatalysts, we achieved 82% and 92% yields of stable imines and α-aa in a membrane-separated cell system, respectively. In a membrane-free system, quaternary or cyclic α-aa could be directly obtained from amines and CO₂ with up to 83% yield. Mechanistic investigations have elucidated that the incorporation of indium (In) yields elevated levels of LA sites. These enhanced LA sites play a pivotal role in facilitating the capture and activation of imines. This function of In-CeO_x, coupled with CO₂ activation mediated by In species, is proven to be crucial for achieving high reactivity and selectivity in the cathodic carboxylation reaction.

中文翻译：

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用胺电化学固定 CO2 合成 α-氨基酸


α-氨基酸 （α-aa） 在制药和化学工业中发挥着重要作用。在这里，我们报道了一种电化学串联系统，该系统耦合了胺的阳极脱氢和亚胺的阴极羧化。基于设计的富含路易斯酸 （LA） 的 CeO₂，以铟（表示为 In-CeO_x）作为阴极电催化剂，我们在膜分离的电池系统中分别实现了 82% 和 92% 的稳定亚胺和 α-aa 产率。在无膜体系中，季铵盐或环状 α-aa 可直接从胺和 CO₂ 中获得，产率高达 83%。机制调查阐明，铟 （In） 的掺入会产生高水平的 LA 位点。这些增强的 LA 位点在促进亚胺的捕获和激活方面起着关键作用。In-CeO_x 的这种功能与 In 物种介导的 CO₂ 激活相结合，被证明对于在阴极羧化反应中实现高反应性和选择性至关重要。