The conventional cathodic electrochemiluminescence (ECL) always requires a more negative potential to trigger strong emission, which inevitably damages the bioactivity of targets and decreases the sensitivity and specificity. In this work, iron single-atom catalysts (Fe–N–C SACs) were employed as an efficient co-reaction accelerator for the first time to achieve the impressively cathodic emission of a luminol–H₂O₂ ECL system at an ultralow potential. Benefiting from the distinct electronic structure, Fe–N–C SACs exhibit remarkable properties for the activation of H₂O₂ to produce massive reactive oxygen species (ROS) under a negative scanning potential from 0 to −0.2 V. The ROS can oxidize the luminol anions into luminol anion radicals, avoiding the tedious electrochemical oxidation process of luminol. Then, the in situ-formed luminol anion radicals will directly react with ROS for the strong ECL emission. As a proof of concept, sensitive detection of the carcinoembryonic antigen was realized by glucose oxidase-mediated ECL immunoassay, shedding light on the superiority of SACs to construct efficient cathodic ECL systems with low triggering potential.

中文翻译：

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单原子铁可实现强低触发电位鲁米诺阴极电化学发光

传统的阴极电化学发光 (ECL) 总是需要更大的负电位来触发强发射，这不可避免地损害了靶标的生物活性，降低了灵敏度和特异性。在这项工作中，铁单原子催化剂（Fe-N-C SACs）首次被用作高效的共反应促进剂，以实现鲁米诺-H ₂ O ₂ ECL 体系在超低电位下的显着阴极发射. 得益于独特的电子结构，Fe-N-C SACs 表现出显着的 H ₂ O _{2活化特性}在0到-0.2 V的负扫描电位下产生大量的活性氧（ROS）。ROS可以将鲁米诺阴离子氧化成鲁米诺阴离子自由基，避免了鲁米诺繁琐的电化学氧化过程。然后，原位形成的鲁米诺阴离子自由基将直接与 ROS 反应以产生强 ECL 发射。作为概念验证，通过葡萄糖氧化酶介导的 ECL 免疫测定实现了对癌胚抗原的灵敏检测，揭示了 SAC 在构建低触发电位的高效阴极 ECL 系统方面的优势。