Phase Engineering and Dispersion Stabilization of Cobalt toward Enhanced Hydrogen Evolution

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-10, Vol.20 (40), p.e2310499-n/a
• Main Authors: Zhang, Chao, Luo, Yihang, Fu, Nianqing, Mu, Songlin, Peng, Jihua, Liu, Yan, Zhang, Guoge
• Format: Article
• Language: English
• Subjects: Carbides; Catalysts; Cobalt; dispersion stabilization; Dispersions; electrocatalyst; Electronic structure; Grain boundaries; High temperature; hydrogen evolution reaction; Hydrogen evolution reactions; Hydrogen production; Interface stability; Metastable phases; phase engineering; Phase transitions; Plasma jets; Polymorphism; Solid phases; Stacking fault energy; water splitting
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202310499

Phase engineering is promising to increase the intrinsic activity of the catalyst toward hydrogen evolution reaction (HER). However, the polymorphism interface is unstable due to the presence of metastable phases. Herein, phase engineering and dispersion stabilization are applied simultaneously to boost the HER activity of cobalt without sacrificing the stability. A fast and facile approach (plasma cathodic electro deposition) is developed to prepare cobalt film with a hetero‐phase structure. The polymorphs of cobalt are realized through reduced stacking fault energy due to the doping of Mo, and the high temperature treatment resulted from the plasma discharge. Meanwhile, homogeneously dispersed oxide/carbide nanoparticles are produced from the reaction of plasma‐induced oxygen/carbon atoms with electro‐deposited metal. The existence of rich polymorphism interface and oxide/carbide help to facilitate H2 production by the tuning of electronic structure and the increase of active sites. Furthermore, oxide/carbide dispersoid effectively prevents the phase transition through a pinning effect on the grain boundary. As‐prepared Co‐hybrid/CoO_MoC exhibits both high HER activity and robust stability (44 mV at 10 mA cm−2, Tafel slope of 53.2 mV dec−1, no degradation after 100 h test). The work reported here provides an alternate approach to the design of advanced HER catalysts for real application. Dispersion stabilized cobalt film with a hetero‐phase structure, Co‐hybrid/CoO_MoC, is fabricated by a fast and facile approach (plasma cathodic electro deposition). The hydrogen evolution reaction (HER) activity is substantially improved due to the presence of rich polymorphism interfaces, and the stability is also significantly enhanced thanks to the pinning effect resulted from the homogeneously dispersed oxide/carbide.