Accurately Regulating the Electronic Structure of NixSey@NC Core–Shell Nanohybrids through Controllable Selenization of a Ni‐MOF for pH‐Universal Hydrogen Evolution Reaction

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2020-11, Vol.16 (44), p.n/a
• Main Authors: Huang, Zhaodi, Xu, Ben, Li, Zongge, Ren, Jianwei, Mei, Hao, Liu, Zhanning, Xie, Donggang, Zhang, Haobing, Dai, Fangna, Wang, Rongming, Sun, Daofeng
• Format: Article
• Language: English
• Subjects: controllable selenization; Density functional theory; Electrocatalysts; Electronic structure; electronic structure regulation; Hydrogen evolution reactions; Metal-organic frameworks; Nanotechnology; NixSey@NC core‐shell nanohybrids; pH‐universal electrocatalysts; Selenides; Sulfuric acid; Transition metals; van der Waals interactions
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202004231

N‐doped carbon‐encapsulated transition metal selenides (TMSs) have garnered increasing attention as promising electrocatalysts for hydrogen evolution reaction (HER). Accurately regulating the electronic structure of these nanohybrids to reveal the underlying mechanism for enhanced HER performances is still challenging and thus requires deep excavation. Herein, a series of pomegranate‐like NixSey@NC core–shell nanohybrids (including Ni0.85Se @ NC, NiSe2@NC, and NiSe@NC) through controllable selenization of a Ni‐MOF precursor is reported. The component of the nanohybrids can be fine‐tuned by tailoring the selenization temperature and feed ratio, through which the electronic structure can be synchronously regulated. Among these nanohybrids, the Ni0.85Se @ NC exhibits the optimum pH‐universal HER performance with overpotentials of 131, 135, and 183 mV in 0.5 m H2SO4, 1.0 m KOH, and 1.0 m PBS, respectively, at 10 mA cm−2, which are attributed to the increased partial density of state at the Fermi level and effective van der Waals interactions between Ni0.85Se and NC matrix explained by density functional theory calculations. Controllable selenization of a Ni‐MOF gives rise to pomegranate‐like NixSey@NC core–shell nanohybrids with tunable stoichiometric ratio of Ni and Se and controlled pyrrolic N‐doping contents. Different NixSey cores encapsulated in N‐doped carbon (NC) shells accurately regulate the electronic structure of NixSey@NC nanohybrids and the effective van der Waals interactions between Ni0.85Se cores and NC shells enable Ni0.85Se@NC nanohybrids pH‐universal hydrogen evolution reaction performances.