Double-layer hybrid chainmail catalyst for high-performance hydrogen evolution

• Published in: Nano energy 2020-06, Vol.72, p.104700, Article 104700
• Main Authors: Tu, Yunchuan, Deng, Jiao, Ma, Chao, Yu, Liang, Bao, Xinhe, Deng, Dehui
• Format: Article
• Language: English
• Subjects: Electrocatalysis; Electron traversing; Graphene-encapsulated metal; Hydrogen evolution reaction; Single-layer molybdenum disulfide
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2020.104700

Developing highly catalytic active but stable MoS2 catalyst for electrochemical hydrogen evolution reaction (HER) performance, requires atomic-level tailoring of the electronic structure, but is greatly challenging. Herein, via precisely growing a double-layer MoS2/graphene hybrid structure encapsulating CoNi nanoalloy (MoS2/(CoNi@G)), we report both significantly enhanced HER activity and stability by the electrons of the CoNi cores traversing through the graphene to the outmost MoS2 layer. It achieves 10 mA cm−2 at a significantly lower overpotential of 150 mV than that of 262 mV over pristine MoS2 nanosheets, and runs stably for over 10000 cyclic voltammetry cycles. The electron traversing effect efficiently tunes the electronic structures of both edge S sites and in-plane S vacancies, resulting in more appropriate adsorption energy of hydrogen on these active centers. It also induces strong electronic interactions between the MoS2 and CoNi@G, which stabilizes the outmost MoS2 layer and thereby significantly improves its catalytic stability. An innovative strategy of atomic-level engineering the electronic structures of single-layer MoS2 is proposed via an electron traversing effect of single-layer graphene-encapsulated CoNi cores. The electrons derived from the encapsulated CoNi metallic cores can traverse through the single-layer graphene to the outmost single-layer MoS2, consequently inducing a strong interaction between the MoS2 and the graphene surface, achieving a higher catalytic activity and stability for hydrogen evolution. [Display omitted] •A novel strategy of precisely growing double-layer MoS2/graphene hybrid chainmail encapsulating CoNi has been presented.•The optimized catalyst achieves an enhanced catalytic activity and stability for hydrogen evolution.•The electrons derived from CoNi cores can traverse through the intermediate graphene layer to the outmost MoS2 shell.•The electronic structures of single-layer MoS2 can be efficiently tuned via an electron traversing effect.•The traversed electrons induce strong electronic interactions between MoS2 and CoNi@G, which stabilizes the MoS2 layer.