Amorphous nickel sulfide nanoparticles anchored on N-doped graphene nanotubes with superior properties for high-performance supercapacitors and efficient oxygen evolution reaction

Abstract

Amorphous nickel sulfide nanoparticles electrodeposited on N-doped graphene nanotubes exhibit excellent electrochemical performance for asymmetric supercapacitors and the OER.

(Fe,Ni)9S8 Nanosheets on a Three‐Dimensional Conductive Substrate for Efficient Oxygen Evolution Reaction Electrocatalysis

“…A large number of studies have demonstrated that the OER activity of nickel sulfide can be improved by coupling with highly conductive materials such as nickel foam, [12a,15] graphene, [14,16] carbon nanotubes, [11b,13] and metal‐organic frames, [17] etc. Zou and co‐workers reported a synthetic method that leads to in situ growth of high‐index faceted Ni 3 S 2 nanosheet arrays on nickel foam (NF), with excellent OER catalytic activity and stability for the first time.…”

“…Wang and co‐authors constructed layered 2D/2D NiS/graphene heterojunction structure, which exhibited high surface‐active sites and excellent conductivity, achieved by 300 mV overpotential at the current density of 10 mA cm −2 [16] . Li et al prepared thin NiS nanoparticles/N‐doped graphene nanotubes (for N‐GNT@NSN) heterojunction structure via a simple electrodeposition method, which the N‐GNT provides a fast channel for electronic transmission and promotes charge transfer to improves the catalytic activity of OER [11b] . Antonietti and co‐workers directly synthesized NiS nanosheets on stainless steel mesh materials, which demonstrated excellent OER catalytic performance [19] .…”

“…Herein, we report thin (Fe,Ni) 9 S 8 nanosheets (FNS NSs) electrodeposited on the three‐dimensional Fe/Fe 3 O 4 nanoislands/carbon cloth (Fe NIs/CC) substrate towards the OER. The corresponding merits of this rational design are summarized as follows: a, Fe/Fe 3 O 4 nanoislands (Fe NIs) have a high conductivity and a large specific surface area, (Fe,Ni) 9 S 8 nanosheets structure coupling Fe NIs improves the specific surface area and exposes more accessible active sites; [21] b, (Fe,Ni) 9 S 8 nanosheets are synthesized directly on Fe/Fe 3 O 4 nanoislands that can reduce the interface contact resistance and accelerate the rate of charge transfer; [11b,20] c, synergism between transition metal Fe and Ni, can also enhance the intrinsic catalytic activity of the catalyst [22] . The as‐prepared 3D FNS NSs@Fe NIs/CC exhibited excellent OER performance with an overpotential of 147 mV at a current density of 10 mA cm −2 in 1 M KOH alkaline solution.…”

“…Intentionally, the selected area electron diffraction (SAED) pattern (Figure 2f) was performed to confirm the crystal structure of (Fe,Ni) 9 S 8 with the rings corresponding to (400), (311), (420), (531, (533) of (Fe,Ni) 9 S 8 . The 2D structure of (Fe,Ni) 9 S 8 nanosheets can increase the close contact area of the electrolyte and the number of active sites, thus improving the electrocatalytic performance [11b,20] . The fact that FNS NSs are synthesized directly on Fe NIs, it can reduce the interface contact resistance and accelerate the rate of charge transfer, which is an important factor for superior OER performance of FNS NSs@Fe NIs/CC.…”

“…Additionally, compared with NiS NSs/CC, the incorporation of Fe can significantly improve the conductivity due to the synergy effect between Fe and Ni. It has been well studied that the synergistic electronic interplay between Fe and Ni can modify the adsorption process of the intermediates during OER, thus accelerate the reaction kinetics and enhance the electrocatalytic efficiency [11b,20,45] . In addition, the synergistic effect of Fe and Ni also plays an important role in determining the surface morphology to expose more active sites and facilitate charge transfer [46] .…”