Surfactant‐Mediated Morphological Evolution of MnCo Prussian Blue Structures

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2020-10, Vol.16 (43), p.e2004614-n/a
• Main Authors: Wang, Xian, Dong, Anrui, Zhu, Ziyi, Chai, Lulu, Ding, Junyang, Zhong, Li, Li, Ting‐Ting, Hu, Yue, Qian, Jinjie, Huang, Shaoming
• Format: Article
• Language: English
• Subjects: carbon nanotubes; Epitaxial growth; Graphitization; Kinetics; manganese cobalt carbide; Morphology; Nanocrystals; Nanomaterials; Nanoparticles; Nanotechnology; oxygen reduction reaction; Oxygen reduction reactions; Pigments; prussian blue analogue; Pyrolysis; Reaction time; Sodium dodecyl sulfate; Thermodynamics
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202004614

In the preparation of nanomaterials, the kinetics and thermodynamics in the reaction can significantly affect the structures and phases of nanocrystals. Therefore, people are keen to adopt various synthetic strategies to accurately assemble the target nanocrystals, and reveal the underlying mechanism of the formation of specific structures. In this work, the total reaction time is adjusted to let the prepared MnCo Prussian blue analogous (MnCoPBA) crystals show four evolving morphological changes at different stages with the assistance of sodium dodecyl sulfate. Furthermore, it is clearly observed that the epitaxial growth along the (100) plane on the shell of MnCoPBA nanocrystals is favored, and the thermodynamics and kinetics in the morphology change process are analyzed in detail. Through the simple pyrolysis, MnCoPBA crystals can be successfully converted into the corresponding carbon composites, of which Mn2Co2C nanoparticles are evenly distributed in highly graphitized carbon matrix. Among them, PBA‐III‐700 performs good oxygen reduction reaction performance in alkaline solution with the half‐wave potential of 0.801 V and diffusion‐limited current density of 5.36 mA cm−2, and its zinc‐air battery exhibits the peak power density of 103.4 mW cm−2 competitive with commercial Pt/C. A surfactant‐mediated one‐pot hydrothermal method is developed to prepare MnCoPBA crystals, which exhibit morphological changes at five growth stages. As the reaction time goes, the shell of the MnCoPBA crystal grows epitaxially along the (100) plane and the core is etched along the (111) plane.