Self-Interconnected Porous Networks of NiCo Disulfide as Efficient Bifunctional Electrocatalysts for Overall Water Splitting

Abstract

Electrochemical splitting of water has been viewed as a highly efficient technique to produce clean hydrogen and oxygen energy. However, designing inexpensive multifunctional electrocatalysts with high performance is a great challenge. Here, a unique three-dimensional catalyst of self-interconnected porous Ni-Co disulfide networks grown on carbon cloth [(NiCo)S nanowires (NWs)/CC] was prepared by a facile hydrothermal method coupled with further low-temperature sulfuration strategy. As a bifunctional electrocatalyst, (NiCo)S NWs/CC exhibits a remarkable activity to catalyze both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). To drive a current density of 100 mA cm, (NiCo)S NWs/CC needs the overpotentials of 156 mV in 0.5 M HSO solution and 334 mV in 1.0 M KOH solution for HER, respectively. Moreover, when used as a catalyst of OER, (NiCo)S NWs/CC needs an overpotential of 295 mV to produce a current density of 100 mA cm. The excellent electrochemical properties are mainly attributed to the synergetic catalysis of a Ni-Co-based bimetallic disulfide, the porous network structure, and the high conduction of CC. Moreover, the two-electrode alkaline water-splitting system constructed by (NiCo)S NWs/CC only needs a low cell voltage of 1.57 V to approach 10 mA cm. This work offers more new insights for the design and preparation of the non-noble metal catalysts based on transition metal sulfides with excellent electrocatalytic performance in overall water splitting.

Metal-organic Framework-driven Porous Cobalt Disulfide Nanoparticles Fabricated by Gaseous Sulfurization as Bifunctional Electrocatalysts for Overall Water Splitting

“…S14a). Although the Co and O of MOF-driven CoS 2 after OER durability test were uniformly distributed, signal of S was relatively weak due to the formation of surface CoOOH 54 . XPS analysis was conducted (Fig.…”

“…S14b–d). The peak of CoOOH (783 eV) was observed in Co 2p spectrum 54,55 . In S 2p spectrum, only S-O peaks were featured 6,56 .…”

Prussian Blue Analogues–Derived CoFe–B Nanocubes with Increased Specific Surface Area and Modulated Electronic Structure as Enhanced Oxygen Evolution Electrocatalysts

“…[8,9] Therefore, exploring highly efficient, earth-abundant, and stable catalysts is vital for facilitating the development of electrocatalysis. Among the multitudinous reported catalysts, 3D transition metal-based catalysts (including phosphides, [10][11][12] sulfides, [13][14][15] nitrides, [16][17][18] borides, [19][20][21] (oxy)hydroxides, [22] and so on) have been explored as potential alternatives for the half reactions of water splitting.…”

Ultrafine Cobalt‐Doped Iron Disulfide Nanoparticles in Ordered Mesoporous Carbon for Efficient Hydrogen Evolution

“…[11] Besides the intrinsic activity, the performance of FeS 2 catalyst also depends on the density of active sites. [16] Designing nanostructures like nanowires, nanosheets and nanorods is considered to be an effective method to expose more active sites of a catalyst. [17][18][19] Among various nanostructures, zero-dimensional (0D) nanoparticles (NPs) enable maximum exposure of active sites due to their ultra-small size and large number of coordinatively unsaturated sites, thus significantly improving the HER activity of the catalyst.…”

“…It has been reported that cobalt (Co) doping significantly elevated the Fermi level of FeS 2 , and facilitated electron transfer from the FeS 2 surface to H, thereby granting it with higher HER activity . Besides the intrinsic activity, the performance of FeS 2 catalyst also depends on the density of active sites . Designing nanostructures like nanowires, nanosheets and nanorods is considered to be an effective method to expose more active sites of a catalyst .…”