In view of the optimal catalytic efficiency (∼100%), single-atom site catalysts are being widely exploited in a range of areas including organic synthesis, energy conversion, environmental remediation, biotherapy, etc. However, low loading ratio of the unitary active sites on single-atom site catalysts dramatically hinders the remarkable improvement of their catalytic activity. Hereby, a facile low-temperature reduction protocol was adopted for synthesizing CoN₄-supported Co₂N metal clusters on graphitic carbon nitride, which show the remarkably superior chemiluminescent (CL) catalytic capacity than some reported pure single-atom site catalysts. Nitrogen-encapsulated Co₂N clusters coupled with isolated Co–N₄ moieties (Co₂N@Co–N₄) endowed the synergetic catalysts with high Co content of 53.2 wt%. Through X-ray absorption spectroscopy, the synergetic active sites (Co₂N@Co–N₄) afforded the CoN₄-supported Co₂N clusters with the remarkable catalytic activity for accelerating the decomposition of H₂O₂ to produce extensive superoxide radical anion rather than singlet oxygen or hydroxyl radical. Therefore, the CoN₄-supported Co₂N clusters possessed the superb enhancement effect on luminol-H₂O₂ CL reaction by ∼22829 times. The CoN₄-supported Co₂N clusters were utilized as signal probes to establish a CL immunochromatographic assay (ICA) platform for quantitating mycotoxins. Herein, aflatoxin B1 was employed as a mode analyte and the limit of detection was as low as 0.33 pg mL⁻¹ (3σ). As a proof-of-principle work, the developed ICA protocol was successfully employed on the detection of aflatoxin B1 spiked in Angelica dahurica and Ganoderma lucidum with acceptable recoveries of 84.0–107.0%. The ideal practicability of the work elucidates that CoN₄-supported Co₂N clusters showed a new perspective for developing the sensitive CL biosensing.

鉴于最佳催化效率（~100%），单原子位点催化剂在有机合成、能量转换、环境修复、生物治疗等领域得到广泛应用。单原子位点催化剂上的位点极大地阻碍了其催化活性的显着提高。因此，采用一种简便的低温还原方案在石墨氮化碳上合成 CoN ₄负载的 Co ₂ N 金属簇，其化学发光（CL）催化能力比一些报道的纯单原子位点催化剂具有显着优越的化学发光（CL）催化能力。氮包封的 Co ₂ N 簇与分离的 Co-N ₄部分（Co₂ N@Co–N ₄ ) 赋予协同催化剂以 53.2 wt% 的高 Co 含量。通过X射线吸收光谱，协同活性位点（Co ₂ N@Co–N ₄）提供了CoN ₄负载的Co ₂ N簇，具有显着的催化活性，可加速H ₂ O ₂分解产生大量超氧自由基阴离子而不是单线态氧或羟基自由基。因此，CoN ₄负载的Co ₂ N团簇对鲁米诺-H ₂ O ₂ CL反应的增强效果提高了～22829倍。CoN ₄支持的Co ₂ N 簇被用作信号探针，以建立用于定量霉菌毒素的 CL 免疫色谱分析 (ICA) 平台。在此，使用黄曲霉毒素B1作为模式分析物，检测限低至0.33 pg mL ^-1 (3σ)。作为一项原理验证工作，开发的 ICA 方案成功用于检测白芷和灵芝中添加的黄曲霉毒素 B1 ，可接受的回收率为 84.0–107.0%。该工作的理想实用性阐明了以CoN ₄为载体的Co ₂ N簇为开发灵敏的CL生物传感提供了新的视角。