Increasing the mass loading of transition metal single atoms coordinated with nitrogen in carbon-based materials (M-N-C) is still challenging. Herein, inspired by the bioconcentration effect in the living body, a biochemistry strategy for the synthesis of Fe-N-C single atoms is demonstrated. Through introducing ferrous glycinate into the growth of fungus, the Fe atoms are bioconcentrated in hyphae. The highly dispersed Fe-N-C single atoms in hyphae-derived carbon fibers (labeled as Fe-N-C SA/HCF) are prepared by the pyrolysis of Fe-riched hyphae. In the bioconcentration process, the uptake of Fe ions by hyphae promotes the secretion of glutathione and ferritin, which provides additional coordination sites for Fe ions. Accordingly, the mass content of Fe in bioconcentrated Fe-N-C SA/HCF reaches 4.8%, which is 5.3 times larger than that of the sample prepared by the conventional pyrolysis process. The present bioconcentration strategy is further extended to the preparation of Co, Ni, and Mn single atoms. Owing to the high content of Fe-N-C single atoms, Fe-N-C SA/HCF shows the onset potential (Eonset ) of 0.931 V versus reversible hydrogen electrode (RHE) and half-wave potential (E1/2 ) of 0.802 V versus RHE in oxygen reduction reaction measurements, which is comparable to the commercial Pt/C catalysts.

中文翻译：

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通过生物浓缩策略促进金属单原子的负载。

在碳基材料（MNC）中，增加与氮配位的过渡金属单原子的质量负载仍然是一项挑战。在此，受生物体内生物富集效应的启发，证明了用于合成Fe-NC单原子的生物化学策略。通过将甘氨酸亚铁引入真菌的生长，Fe原子被生物浓缩在菌丝中。通过富含富铁的菌丝的热解制备在衍生自菌丝的碳纤维中的高度分散的Fe-NC单原子（标记为Fe-NC SA / HCF）。在生物浓缩过程中，菌丝对铁离子的吸收促进了谷胱甘肽和铁蛋白的分泌，从而为铁离子提供了更多的配位点。因此，生物浓缩的Fe-NC SA / HCF中的Fe的质量含量达到4.8％，为5。比通过常规热解工艺制备的样品大3倍。当前的生物浓缩策略进一步扩展到Co，Ni和Mn单原子的制备。由于Fe-NC单原子含量高，Fe-NC SA / HCF相对于可逆氢电极（RHE）的起始电势（Eonset）为0.931 V，相对于RHE的半波电势（E1 / 2）为0.802 V在氧还原反应测量中，可与市售Pt / C催化剂相比。