Jiang Lili, Duan Jingjing, Zhu Junwu, Chen Sheng, Antonietti Markus
Key Laboratory for Soft Chemistry and Functional Materials (Nanjing University of Science and Technology) , Ministry of Education , Nanjing , 210094 , China.
School of Chemical Engineering , The University of Adelaide , Adelaide , SA 5005 , Australia.
ACS Nano. 2020 Feb 25;14(2):2436-2444. doi: 10.1021/acsnano.9b09912. Epub 2020 Jan 29.
Metal clusters, an emerging category of materials with molecular metal dispersity, have been proposed for versatile applications. In this work, we show an unexpected function of metal clusters, which can contribute to preparing 2D/2D superlattice-like heterostructures. The key step is to use metal clusters to adjust the surface charge of 2D nanosheets and, consequently, match the charge negativities per surface area for different 2D nanosheets, which facilitate the electrical-driven assembly of these nanosheets into a superlattice-like heterostructure in aqueous solutions. Accordingly, iron-cluster-directed cationic Fe-N-C nanosheets (Zeta potential: +30.4 mV) have been assembled with anionic MXene (Zeta potential: -39.7 mV) to produce a superlattice-like heterostructure characteristic of a lateral size of around tens of nanometers, a surface area of 30 m g, and ultrathickness of several nanometers with repeated dimensions of 0.4 and 2.1 nm. Potential application of the synthesized Fe-N-C/MXene heterostructure has been demonstrated for electrocatalytic oxygen reduction reaction (ORR) that shows a positive onset potential of 0.92 V, four-electron transfer pathway, and strong durability of 20 h in alkaline electrolyte. This work suggests that metal clusters can assist the assembly of low-dimensional architectures for energy-related applications.
金属簇是一类新兴的具有分子金属分散性的材料，已被提出用于多种应用。在这项工作中，我们展示了金属簇的一种意想不到的功能，它有助于制备二维/二维超晶格状异质结构。关键步骤是使用金属簇来调节二维纳米片的表面电荷，从而使不同二维纳米片的每单位表面积电荷负值相匹配，这有助于在水溶液中通过电驱动将这些纳米片组装成超晶格状异质结构。因此，铁簇导向的阳离子型Fe-N-C纳米片（ζ电位：+30.4 mV）已与阴离子型MXene（ζ电位：-39.7 mV）组装在一起，以产生一种超晶格状异质结构，其横向尺寸约为几十纳米，表面积为30 m²/g，超厚度为几纳米，重复尺寸为0.4和2.1 nm。合成的Fe-N-C/MXene异质结构在电催化氧还原反应（ORR）中的潜在应用已得到证明，该反应在碱性电解质中显示出0.92 V的正起始电位、四电子转移途径和20小时的强耐久性。这项工作表明，金属簇可以辅助组装用于能源相关应用的低维结构。
