Hierarchical MoS2/Ni3S2 core-shell nanofibers for highly efficient and stable overall-water-splitting in alkaline media. (December 2018)

• Record Type: Journal Article
• Authors: Wang, Faze; Wu, Hao; Sun, Hong; Ma, Li; Shen, Wenzhong; Li, Yanbo; Zheng, Maojun
• Is Part Of: Materials today energy. Volume 10(2018)
• Page Start: 214
• Page End: 221
• Publication Date: 2018-12
• Subjects: Molybdenum disulfide -- Ammonium intercalation -- Earth abundant catalyst -- Hydrogen evolution reaction -- Overall water splitting; Energy development -- Periodicals; Energy industries -- Periodicals; Power resources -- Periodicals; Energy policy -- Periodicals; Energy development; Energy industries; Energy policy; Power resources; Electronic journals; Periodicals; 621.042
• DOI: 10.1016/j.mtener.2018.09.004
• Languages: English
• ISSNs: 2468-6069

Abstract

Abstract: Non-noble metal electrocatalysts replacing Pt catalyst for efficient hydrogen-evolution reaction (HER) are highly desired to achieve sustainable production of H2 through water splitting. In this paper, we report a novel ammonium intercalated MoS2 /Ni3 S2 core-shell nanofibers on graphene-Ni foam by a facile method. Such hierarchical nanostructures provide abundant active sites for hydrogen evolution. Furthermore, DFT calculation demonstrates that the intercalated ammonium ions improve the chemisorption of protons for MoS2, thus further enhancing HER activity. The synthesized MoS2 /Ni3 S2 nanofiber cathode exhibits an overpotential of 109 mV at 10 mA cm −2 in 1 M KOH electrolyte – the lowest overpotential reported so far among any earth-abundant cathodes working in strong alkaline condition. Combining with a nickel iron layered double hydroxide anode, stable overall water splitting with a low potential of 1.59 V at 10 mA cm −2 is achieved in 1 M KOH for 100 h. Graphical abstract: Earth-abundant MoS2 has demonstrated its promise as an attractive non-noble metal HER catalyst, but it exhibits poor HER activities in alkaline media. Here, we successfully design and fabricate a hierarchical MoS2 /Ni3 S2 core-shell nanofibers on graphene-Ni foam, resulting an extremely low overpotential of 109 mV at 10 mA cm −2 in 1 M KOH electrolyte. DFT calculation reveals that intercalated ammonium ions improve the chemisorption of protons for MoS2, thus further enhancing HER activity. Combining with a nickel iron layered double hydroxide anode, stable overall water splitting with a low potential of 1.59 V at 10 mA cm −2 is achieved for 100 h. Highlights: Facile synthesize hierarchical MoS2 /Ni3 S2 core-shell nanofibers with intercalated ammonium. DFT calculation reveals intercalated ammonium in MoS2 improve the chemisorption of protons. Low overpotential of ca. 109 mV at 10 mA cm −2 in strong alkaline media. Stable overall water splitting with a potential of 1.59 V at 10 mA cm −2 for 100 h.