Key Laboratory of Fuel Cell Technology of Guangdong Province, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China.
Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, 116023, China.
Small. 2021 Feb;17(6):e2006178. doi: 10.1002/smll.202006178. Epub 2020 Dec 28.
Nitrogen-coordinated single-atom catalysts (SACs) have emerged as a new frontier for accelerating oxygen reduction reaction (ORR) owing to the optimal atom efficiency and fascinating properties. However, augmenting the full exposure of active sites is a crucial challenge in terms of simultaneously pursuing high metal loading of SACs. Here, petal-like porous carbon nanosheets with densely accessible Fe-N moieties (FeNC-D) are constructed by combining the space-confinement of silica and the coordination of diethylenetriaminepentaacetic acid. The resulted FeNC-D catalyst possesses an enhanced mesoporosity and a balanced hydrophobicity/hydrophilicity, which can facilitate mass transport and advance the exposure of inaccessible Fe-N sites, resulting in efficient utilization of active sites. By virtue of the petal-like porous architecture with maximized active site density, FeNC-D demonstrates superior ORR performance in a broad pH range. Remarkably, when utilized as the air cathode in Zn-air battery (ZAB) and microbial fuel cell (MFC), the FeNC-D-based device displays a large power density (356 mW cm for ZAB and 1041.3 mW m for MFC) and possesses remarkable stability, substantially outperforming the commercial Pt/C catalyst.
氮配位的单原子催化剂（SACs）因其最佳的原子效率和迷人的性质而成为加速氧还原反应（ORR）的新前沿。然而，提高活性位的完全暴露是同时追求 SACs 的高金属负载的一个关键挑战。在这里，通过结合二氧化硅的空间限制和二乙烯三胺五乙酸的配位作用，构建了具有密集可及的 Fe-N 部分（FeNC-D）的花瓣状多孔碳纳米片。所得的 FeNC-D 催化剂具有增强的中孔性和平衡的疏水性/亲水性，这可以促进质量传递并促进不可接近的 Fe-N 位的暴露，从而有效地利用活性位。凭借具有最大化活性位密度的花瓣状多孔结构，FeNC-D 在很宽的 pH 范围内表现出优异的 ORR 性能。值得注意的是，当用作锌空气电池（ZAB）和微生物燃料电池（MFC）的空气阴极时，基于 FeNC-D 的装置显示出大的功率密度（ZAB 为 356 mW cm，MFC 为 1041.3 mW m）和卓越的稳定性，大大优于商业 Pt/C 催化剂。
