State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications, Beijing, 100876, China.
Nat Commun. 2019 Feb 5;10(1):606. doi: 10.1038/s41467-019-08484-8.
Temperature can govern morphologies, structures and properties of products from synthesis in solution. A reaction in solution at low temperature may result in different materials than at higher temperature due to thermodynamics and kinetics of nuclei formation. Here, we report a low-temperature solution synthesis of atomically dispersed cobalt in a catalyst with superior performance. By using a water/alcohol mixed solvent with low freezing point, liquid-phase reduction of a cobalt precursor with hydrazine hydrate is realized at -60 °C. A higher energy barrier and a sluggish nucleation rate are achieved to suppress nuclei formation; thus atomically dispersed cobalt is successfully obtained in a catalyst for oxygen reduction with electrochemical performance superior to that of a Pt/C catalyst. Furthermore, the atomically dispersed cobalt catalyst is applied in a microbial fuel cell to obtain a high maximum power density (2550 ± 60 mW m) and no current drop upon operation for 820 h.
温度可以控制从溶液合成中得到的产物的形态、结构和性能。由于核形成的热力学和动力学，溶液中低温下的反应可能会导致与高温下不同的材料。在这里，我们报告了一种在具有优异性能的催化剂中通过低温溶液合成原子分散的钴的方法。通过使用具有低冰点的水/醇混合溶剂，在-60°C 下实现了水合肼对钴前体的液相还原。较高的能量势垒和缓慢的成核速率可抑制核的形成；因此，原子分散的钴成功地获得了在用于氧还原的催化剂中，其电化学性能优于 Pt/C 催化剂。此外，原子分散的钴催化剂被应用于微生物燃料电池中，以获得 2550 ± 60 mW m 的高最大功率密度，并且在 820 小时的运行过程中没有电流下降。
