FeS₂/CoS₂ Interface Nanosheets as Efficient Bifunctional Electrocatalyst for Overall Water Splitting

Abstract

Electrochemical water splitting to produce hydrogen and oxygen, as an important reaction for renewable energy storage, needs highly efficient and stable catalysts. Herein, FeS /CoS interface nanosheets (NSs) as efficient bifunctional electrocatalysts for overall water splitting are reported. The thickness and interface disordered structure with rich defects of FeS /CoS NSs are confirmed by atomic force microscopy and high-resolution transmission electron microscopy. Furthermore, extended X-ray absorption fine structure spectroscopy clarifies that FeS /CoS NSs with sulfur vacancies, which can further increase electrocatalytic performance. Benefiting from the interface nanosheets' structure with abundant defects, the FeS /CoS NSs show remarkable hydrogen evolution reaction (HER) performance with a low overpotential of 78.2 mV at 10 mA cm and a superior stability for 80 h in 1.0 m KOH, and an overpotential of 302 mV at 100 mA cm for the oxygen evolution reaction (OER). More importantly, the FeS /CoS NSs display excellent performance for overall water splitting with a voltage of 1.47 V to achieve current density of 10 mA cm and maintain the activity for at least 21 h. The present work highlights the importance of engineering interface nanosheets with rich defects based on transition metal dichalcogenides for boosting the HER and OER performance.

3D Architectures of Quaternary Co‐Ni‐S‐P/Graphene Hybrids as Highly Active and Stable Bifunctional Electrocatalysts for Overall Water Splitting

“…Highly efficient water electrolysis generally requires high-performance electrocatalysts with low overpotential, fast kinetics, and high stability. [9][10][11] Recently, transition-metal hydroxides, [7,12] phosphides, [8,[13][14][15][16] nitrides, [17,18] and chalcogenides [19][20][21][22] have been investigated as promising candidates for bifunctional electrocatalysts. [7,8] The search for earth-abundant, lowcost HER and OER electrocatalysts that are robust, have high activity and stability has triggered numerous efforts to replace noble metal-based materials.…”

“…[7,8] The search for earth-abundant, lowcost HER and OER electrocatalysts that are robust, have high activity and stability has triggered numerous efforts to replace noble metal-based materials. [19,20] Tailoring the compositional engineering of transition metalbased compounds by heteroatom doping or substitution is also an effective strategy to enhance catalytic activities through tuning the electronic structure of the electrocatalysts. In addition, it is uneconomical to produce a monofunctional electrocatalyst for each HER and OER, as this raises the manufacturing cost.…”

“…[9][10][11] Recently, transition-metal hydroxides, [7,12] phosphides, [8,[13][14][15][16] nitrides, [17,18] and chalcogenides [19][20][21][22] have been investigated as promising candidates for bifunctional electrocatalysts. [9,12,17,19,22,34] However, the high surface energy of sheets, which are unstable, leads to the possibility of stacking with surrounding sheets through van der Waals attractions, resulting in a decrease of the active surface area. [23][24][25][26] In addition, according to recent reports, these compounds can operate as highly efficient OER electrocatalysts and could thus be utilized as bifunctional electrocatalysts.…”

Defect‐Rich Heterogeneous MoS2/NiS2 Nanosheets Electrocatalysts for Efficient Overall Water Splitting

“…[16,17] In particular, in situ growing nanosheet nanostructures on conductive substrates, such as Ni foam, carbon cloth, and stainless steel, could supply the efficient pathways for charge transport and provide open channels for rapid release of gas bubbles during OER or HER process. [21,22] The interface engineering could be beneficial to enrich the active sites and promote the electronic transfer, and thus boost the sluggish water splitting efficiency. [21,22] The interface engineering could be beneficial to enrich the active sites and promote the electronic transfer, and thus boost the sluggish water splitting efficiency.…”

Synergism of Interface and Electronic Effects: Bifunctional N‐Doped Ni3S2/N‐Doped MoS2 Hetero‐Nanowires for Efficient Electrocatalytic Overall Water Splitting

“…An emerging trend in this area of research is the development of earth‐abundant transition‐metal‐based bifunctional electrocatalysts that can effectively catalyze both cathodic and anodic reactions in the same electrolyte . In this regard, integrating the properties and functionalities of H 2 ‐ and O 2 ‐evolving electrocatalysts to construct heterogeneous nanostructures is advantageous in improving the efficiency for electrochemical overall water splitting . The origin for the enhancement in electrocatalytic performance of HER–OER bifunctional heterogeneous catalysts is the well‐recognized interface effect, which can greatly promote the reaction kinetics on catalytically active sites .…”