Facile fabrication of a binary NiCo phosphide with hierarchical architecture for efficient hydrogen evolution reactions

Exploring and designing efficient non-noble catalysts formed by element doping and nanostructure modification for the hydrogen evolution reaction (HER) is of critical importance with respect to sustainable resources. Herein, we have prepared a three-dimensional binary NiCo phosphide with hierarchical architecture (HA) composed of NiCoP nanosheets and nanowires grown on carbon cloth (CC) via a facile hydrothermal method followed by oxidation and phosphorization. Due to its unique hierarchical nanostructure, the NiCoP HA/CC electrocatalyst exhibits excellent performance and good working stability for the HER in both acidic and alkaline conditions. The obtained NiCoP HA/CC shows excellent HER activity with a low potential of 74 and 89 mV at 10 mA cm⁻², a small Tafel slope of 77.2 and 99.8 mV dec⁻¹ and long-term stability up to 24 h in acidic and alkaline electrolyte, respectively. NiCoP HA/CC, a non-noble metal material, is a promising electrocatalyst to replace noble metal-based electrocatalysts for the HER.     

Ultrathin WS2 nanosheets vertically aligned on TiO2 nanobelts as efficient alkaline hydrogen evolution electrocatalyst

Highly efficient and durable non-noble metal-based hydrogen evolution electrocatalysts are critical to advance the production of hydrogen energy via alkaline water electrolysis. Herein, we prepared a novel TiO₂@WS₂ hybrid via a facile and scalable two-step hydrothermal strategy combined with selective etching. Benefited from acid-etched TiO₂ nanobelts with rough surface as substrate, ultrathin WS₂ nanosheets nucleated and vertically grew into few layers in the confined configuration with more exposed active edges. Furthermore, the partial incorporation of oxygen in WS₂ inherited from the remaining O–W bonds of tungsten precursor enhanced the electrical conductivity of the hybrid. Therefore, TiO₂@WS₂ hybrid was proved to be efficient and durable electrocatalyst for hydrogen evolution in alkaline medium. Upon optimal conditions, the hybrid only required a small onset overpotential of 95 mV and a low overpotential of 142 mV at 10 mA cm⁻², superior to pristine WS₂ and TiO₂. In addition, better cycling stability during the alkaline HER process was also obtained, indicating its capability in future practical application. The synthesis strategy presents a cost-effective approach to produce efficient WS₂-based HER electrocatalyst for electrochemical water splitting.     

Urchin-like Co0.8-Mn0.2-P/CC nanowires array: a high-performance and cost-effective hydrogen evolution electrocatalyst

Using cost-effective materials to replace precious Pt-based hydrogen evolution reaction (HER) catalysts holds great foreground for energy saving and environmental protection. In this work, we successfully prepared an urchin-like Co_0.8-Mn_0.2-P nanowires array supported on carbon cloth (CC) through a hydrothermal-phosphatization strategy and we also systematically studied its electrocatalytic HER performance. Electrochemical tests demonstrate that our urchin-like Co_0.8-Mn_0.2-P/CC possesses outstanding HER activity in acidic and alkaline media. In 0.5 M H₂SO₄, this urchin-like Co_0.8-Mn_0.2-P/CC only requires an overpotential of 55 mV to drive a current density of 10 mA cm⁻², with the Tafel slope of 55.9 mV dec⁻¹. Similarly, when reaching the same current density, just a particularly low overpotential of 61 mV is required with a corresponding Tafel slope of 41.7 mV dec⁻¹ in 1 M KOH. Furthermore, this electrocatalyst exhibits superior stability with 1000 cycles of cyclic voltammetry and 24 h in the I-T test. Such excellent HER catalytic performance can be attributed to the synergistic effect between Co and Mn atoms and high electrochemical active surface area (ECSA). Our work provides a valuable synthesis strategy of non-precious and high HER performance catalytic material.     

Iron doped mesoporous cobalt phosphide with optimized electronic structure for enhanced hydrogen evolution

We report a self-supporting electrode fabricated by covering iron doped mesoporous cobalt phosphide film on carbon cloth substrate (meso-Fe_xCo_1-xP/CC) for hydrogen evolution reaction (HER). In acidic and alkaline electrolytes, the electrode exhibited excellent catalytic activity and fast kinetics towards the HER, only requiring small overpotentials of 61 mV and 67 mV to drive 10 mA cm^?2, respectively. The superior electrocatalytic activity is attributed to the mesoporous structure with high specific surface area (147.5 m² g^?1) and doping of Fe atom. The mesoporous structure grown on the conductive carbon cloth substrate enables the fully exposure of active sites and the rapid penetration of electrolyte. Additionally, density functional theory (DFT) calculation reveals that the doping of Fe enhances the adsorption of H atoms by shifting the d-band center of Co. Meanwhile, the introduction of Fe lowers the energy barrier for water dissociation, which accelerates the catalytic kinetics in alkaline electrolyte.     

Synthesis of functional Ni2P/CC catalyst and the robust performances in hydrogen evolution reaction and nitrate reduction

The non-precious transition metal phosphides (TMPs) as robust and effective hydrogen evolution reaction (HER) catalysts have attracted enormous attention, due to the merits of earth-abundance, low price, desirable stability and high efficiency. However, the conventional preparation process of this kind of catalyst is inconvenient. Herein, we report a facile approach toward the fabrication of nickel phosphide (Ni₂P) assembled on carbon cloth (CC) via the coupling method of electroless plating and low temperature phosphorization. Then, the crystallinity, morphology and chemical component of fabricated self-supporting Ni₂P/CC catalyst employed for the HER process were characterized, and the HER property was successively evaluated in three types of electrolytes (i.e., acidic, neutral and alkaline solutions). The as-prepared Ni₂P/CC catalyst displays a remarkable HER performance, which can be corroborated by the small Tafel slope (b = 50 mV dec⁻¹), high exchange current density (j₀ = 6.6 × 10⁻² mA cm⁻²), acceptable overpotential (119 mV) to attain the current density of 10 mA cm⁻², as well as the superb stability (<5% decay after 24 h potentiostatic test) in 0.5 M H₂SO₄. In addition, it should be noted that the HER process of Ni₂P/CC catalyst can be competent for the reduction of nitrate from the solution, and an efficiency of 63.2% for this nutrient pollutant is achieved.     

Ni(OH)2/ NiSe2 hybrid nanosheet arrays for enhanced alkaline hydrogen evolution reaction

Developing efficient, non-noble electrocatalysts toward hydrogen evolution reaction (HER) in alkaline electrolytes is of important significance for future energy supplement but still a challenge. Recently, pyrite-type NiSe₂ nanomaterial has been considered as an idea HER electrocatalyst due to its high conductivity, strong corrosion resistance and low cost. However, the HER performance of NiSe₂ in alkaline electrolytes is still unsatisfactory, which is possibly limited to the activate water dissociation in alkaline media. Herein, a novel hybrid electrocatalyst of Ni(OH)₂/NiSe₂ nanosheet arrays on carbon cloth (Ni(OH)₂/NiSe₂/CC) is fabricated, exhibiting excellent HER catalytic activity with a low overpotential of 82 mV to drive a current density of 10 mAcm⁻² as well as maintaining a long-term durability for 12 h in 1.0 M KOH, which is 77 mV less than that of NiSe₂/CC and superior to most recently reported non-noble HER electrocatalysts. In addition, the Tafel slope of Ni(OH)₂/NiSe₂/CC (60 mV dec ⁻¹) is also much smaller than that of NiSe₂/CC (112 mV dec ⁻¹), suggesting a promotion kinetics of HER process for Ni(OH)₂/NiSe₂/CC. Our further experimental results show that the significantly improved activity of Ni(OH)₂/NiSe₂/CC electrode should ascribe to its enlarged active surface, good conductivity and interfacial synergy between Ni(OH)₂ and NiSe₂. The synergetic strategy may provide an efficient way to promote the HER activity of other non-noble transition metal selenides in alkaline electrolyte.     

N-doped graphene supported W2C/WC as efficient electrocatalyst for hydrogen evolution reaction

Tungsten carbides (W₂C and WC) materials, as promising non-precious electrocatalysts, possess highly efficient activity for HER. Herein, N-doped graphene supported tungsten carbide (N–W₂C/WC) nanocomposite is synthesized by spray drying process followed with a two-step pyrolysis treatment, which exhibits a remarkable hydrogen evolution reaction (HER) activity and excellent stability in acidic solution and alkaline solution. N–W₂C/WC displays low overpotentials of 166 mV and 125 mV to achieve a current density of 10 mA cm^?2 and small Tafel slopes of 60.97 and 62.66 mV dec^?1 in 0.5 M H₂SO₄ and 1.0 M KOH, respectively. After 1000 cycles, the electrocatalytic activity of N–W₂C/WC is almost no change in acidic media but slightly decreases in alkaline media. This work might provide a new way to explore high comprehensive performance tungsten-based electrocatalyst for HER.     

Ultra-fine Ru nanoparticles decorated V2O3 as a pH-universal electrocatalyst for efficient hydrogen evolution reaction

Developing high-efficiency electrocatalysts viable for pH-universal hydrogen evolution reaction (HER) has attracted great interest because hydrogen is a promising renewable energy carrier for replacing fossil fuels. Herein, we present a facile strategy for fabricating ultra-fine Ru nanoparticles (NPs) decorated V₂O₃ on the carbon cloth substrates as efficient and stable pH-universal catalysts for HER. Benefiting from the metallic property and electronic conductivity of V₂O₃ matrix, the optimized hybrid (Ru/V₂O₃-CC) exhibits excellent HER activities in a wide pH range, achieving lower overpotentials of 184, 219, and 221 mV at 100 mA cm⁻² in 0.5 M H₂SO₄, 1.0 M KOH and 1.0 M phosphate-buffered saline, respectively. Moreover, the electrode remains superior stability with negligible degradation after 5000 cyclic voltammetry scanning whether in acidic, alkaline or neutral media. Experimental results, combined with theoretical calculations, demonstrate that the interaction between Ru NPs and the support V₂O₃ induces the local electronic density diversity, allowing optimization of the adsorption energy of Ru towards hydrogen intermediate H1, thus favoring the HER process.     

Structure and electrocatalytic hydrogen evolution performance of Mo2C thin films prepared by magnetron sputtering

Mo₂C, which has a unique electronic structure similar to the electronic structure of Pt, is considered as the material with the greatest potential to replace Pt as a catalyst for the electrocatalytic hydrogen evolution reaction (HER). However, Mo₂C thin films have not attracted enough attention in the field of electrocatalysis. This work proposes a method for preparing Mo₂C thin films as a catalyst for electrocatalytic HER through radiofrequency magnetron sputtering. The HER activity of the Mo₂C thin film in acidic and alkaline media is studied by changing the deposition power of the Mo₂C target and doping Ni for structural modification. Results show that increasing the deposition power of Mo₂C can significantly enhance the HER activity of the films in acidic and alkaline media, and metal Ni doping can further enhance the HER activity of the Mo₂C films. In an alkaline environment at a current density of 10 mA cm⁻², the films demonstrate an overpotential of as low as 163 mV with a Tafel slope of 107 mV·dec⁻¹. In acidic media, the films present the corresponding overpotential of 201 mV and a Tafel slope of as low as 96 mV·dec⁻¹. Moreover, the Ni-doped Mo₂C films have excellent HER stability. The synergy between doped Ni and Mo vacancies optimizes the strength of the Mo–H bond and the adsorption and desorption equilibrium of active H, thus enhancing HER kinetics. This work guides the possible structural design of Mo₂C thin films for electrocatalytic HER.     

Synthesis of ultrafine ruthenium phosphide nanoparticles and nitrogen/phosphorus dual-doped carbon hybrids as advanced electrocatalysts for all-pH hydrogen evolution reaction

Pt-group metal phosphides are widely utilized as efficient electrocatalysts for hydrogen evolution reaction (HER), whereas most of the synthetic strategies are complicated, dangerous, and toxic with the use of large amount of nitrogen (N) and/or phosphorus (P) sources. Here, we report the synthesis of ruthenium phosphide nanoparticles (NPs) confined into N/P dual-doped carbon by pyrolyzing self-prepared ruthenium-organophosphine complex using 1,3,5-triaza-7-phosphadamantane (PTA) as the ligand and N/P sources. The achieved S–RuP₂/NPC displayed excellent electrocatalytic activity (overpotentials of 19, 37, and 49 mV in alkaline, neutral, and acidic media, respectively, at 10 mA cm⁻²) toward HER at all pH ranges. The high performance of S–RuP₂/NPC must be ascribed to the homogeneously distributed and P-rich RuP₂ NPs with the diameter of 3.29 nm on the NPC surface, which can considerably improve the atom utilization for HER. The present synthetic strategy not only avoids the use of additional N/P sources but also the generation of flammable and toxic PH₃ gas. This synthetic strategy can be extended to prepare other traditional metal phosphides for electrocatalytic applications.     

Carbon supported bifunctional Rh–Ni(OH)2/C nanocomposite catalysts with high electrocatalytic efficiency for alkaline hydrogen evolution reaction

Pt group metals display lower HER activity in alkaline solution than in acidic solution, because they are inefficient in the water dissociation step (Volmer step). Compared with Pt, the activity difference of Rh in alkaline and acidic media is much smaller. Meanwhile, Ni(OH)₂ is proved to be an effective catalyst for water dissociation. Therefore, Rh–Ni(OH)₂/C nanocomposites with different Rh:Ni(OH)₂ ratios were synthesized by a co-deposition/partial reduction method, and their microstructures as well as electrocatalytic properties were studied. The results show that Rh and Ni(OH)₂ display synergistic effect in Rh–Ni(OH)₂/C nanocomposites. The Rh–Ni(OH)₂/C nanocomposite with a molar ratio of Rh to Ni(OH)₂ of 1:1 exhibits the highest activity. It shows an overpotential of 36 mV at 10 mA cm^?2 and a Tafel slope of 32 mV dec^?1 for HER in alkaline media, which is superior to commercial Pt/C. In addition, the Rh–Ni(OH)₂/C (1:1) nanocomposite shows excellent durability in alkaline media as well.     

Facile construction of porous and heterostructured molybdenum nitride/carbide nanobelt arrays for large current hydrogen evolution reaction

The development of cost-effective, highly efficient and stable electrocatalysts for alkaline water electrolysis at a large current density has attracted considerable attention. Herein, we reported a one-dimensional (1D) porous Mo₂C/Mo₂N heterostructured electrocatalyst on carbon cloth as robust electrode for large current hydrogen evolution reaction (HER). The MoO₃ nanobelt arrays and urea were used as the metal and non-metal sources to fabricate the electrocatalyst by one-step thermal reaction. Due to the in-situ formed abundant high active interfaces and porous structure, the Mo₂C/Mo₂N electrocatalyst shows enhanced HER activity and kinetics, as exemplified by low overpotentials of 54, 73, and 96 mV at a current density of 10 mA cm^?2 and small Tafel slopes of 48, 59 and 60 mV dec^?1 in alkaline, neutral and acid media, respectively. Furthermore, the optimal Mo₂C/Mo₂N catalyst only requires a low overpotential of 290 mV to reach a large current density of 500 mA cm^?2 in alkaline media, which is superior to commercial Pt/C catalyst (368 mV) and better than those of recently reported Mo-based electrocatalysts. This work paves a facile strategy to construct highly efficient and low-cost electrocatalyst for water splitting, which could be extended to fabricate other heterostructured electrocatalyst for electrocatalysis and energy conversion.     

WS2/NiSx heterojunction nanosheet clusters: A highly efficient electrocatalyst for hydrogen evolution reaction

The development of highly active and stable electrocatalysts is essential to solve energy and environmental problems and realize sustainable social and economic development. Herein, we synthesized a bimetallic sulfide material by a kinetically controlled low-temperature solid-phase reaction. The bimetallic sulfide improves the conductivity of the electrocatalysts by optimized electronic structure, and the coupling effect at the heterogeneous interface of WS₂ and NiS_x increases the charge density on the S site at W–S–Ni, making it easier for the electrocatalysts to trap the active material in solution. In addition, nanosheet clusters expose abundant catalytic sites, which together improve hydrogen evolution reaction (HER) for catalytic activity. Optimized WS₂/NiS_x composite show near-precious metal catalyst activity with an overpotential at 10 mA cm^?2 of only 72 mV in alkaline media, which exhibits excellent catalytic stability and outperforms most non-precious metal electrocatalysts.     

Molten salt strategy to synthesize alkali metal-doped Co9S8 nanoparticles embedded,N, S co-doped mesoporous carbon as hydrogen evolution electrocatalyst

A molten salt strategy was proposed to prepare a series of electrocatalysts for hydrogen evolution reaction (HER) with salts as templates, which consisted of Co₉S₈ nanoparticles (NPs) and N, S co-doped mesoporous carbons. The porosities, heteroatoms contents, and crystalline structures of the final electrocatalysts were determined by the types of salts and the calcining temperatures. When KCl/NaCl, KCl/LiCl, and NaCl/CaCl₂ were adopted as the molten salts, Co₉S₈ NPs embedded, N, S co-doped carbons were obtained. However, when CaCl₂ and ZnCl₂ were used as the molten salts, Co₉S₈ could not be synthesized. The characterization results exhibited that alkali metal atoms could be introduced in the lattices of Co₉S₈. The combination of experimental and theoretical results revealed that Na and K atoms doping improved the electrocatalytic performance for HER. GTCo900-KCl/NaCl possessed the best HER activity, delivering a current density of 10 mA cm⁻² at 54 mV in acidic media, 142 mV in neutral media, and 103 mV in alkaline media.     

Electrocatalytic hydrogen evolution on iron-cobalt nanoparticles encapsulated in nitrogenated carbon nanotube

Using low-cost nonprecious metals to replace Pt as hydrogen evolution reaction (HER) electrocatalyst is promising, but still limited by their efficiency and stability. Herein, with low-cost dicyandiamide and metal salts as precursor, FeCo alloy nanoparticles encapsulated in nitrogenated carbon nanotubes (FeCo-NCNTs) were facially synthesized as efficient HER electrocatalyst. Addition of iron as second element, though not facilitating the formation of carbon nanotube, was utilized to improve the physicochemical properties of metals. Via optimizing the atomic molar ratios of Fe/Co nanoparticles, the optimal Fe_0.4Co_0.6-NCNTs with thin carbon shell (c.a. 5–10 layer) and equally distribution of embedded alloy nanoparticles was found with outstanding HER activity. To achieve a current density of 10 mA cm⁻², only overpotential of 50 mV, 157 mV and 202 mV were needed in acidic (0.5 M H₂SO₄), alkaline (1 M KOH), and neutral solutions. Its higher electrochemically active surface areas and lower electron transfer resistance may contribute to the excellent electrocatalytic HER. Furthermore, the illustrated current density slightly changed over 20 h, suggesting excellent stability. Hence, the present method provides cost-effective, high efficiency, and stable materials in developing the sustainable energy conversion systems.     

Tuning of electrocatalytic activity of mixed metal dichalcogenides supported NiMoP coatings for alkaline hydrogen evolution reaction

The mixed metal dichalcogenides combination of WS₂–MoS₂ was coated onto Cu substrate by electroless NiMoP plating technique and the electrocatalytic hydrogen evolution reaction (HER) performance was investigated. The enhanced structural, morphological parameters and boosted electrocatalytic performance of the various metal-metal molar ratio of WS₂–MoS₂ onto NiMoP plate were identified under variable operating conditions and it was successfully evaluated by various characterization techniques. The well-defined crystalline nature, phase, particle size, structure, elemental analysis and surface morphology of prepared coatings were analyzed by FESEM, XRD, AFM and EDS mapping. The electrochemical analysis was performed using open circuit potential (OCP) analysis, chronoamperometry (CA), electrochemical impedance spectroscopy (EIS), Tafel curves, linear sweep voltammetry (LSV), cyclic voltammetry (CV) and polarization studies to find the activity of prepared electrocatalyst towards electrochemical hydrogen evolution reactions. The performance of bare NiMoP and WS₂–MoS₂/NiMoP plates were compared and found that the HER activity of NiMoP can be reinforced by composite incorporation through the synergic effect arises with in the catalytic system, which improves surface roughness and enhances the magnitude of electrocatalyst toward HER. The achievement of enhanced catalytic performance of coatings was authenticate by the kinetic parameters such as decreases in Tafel slope (98 mV dec^?1), enhanced exchange current densities (9.32 × 10^?4 A cm^?2), and a lower overpotential. The consistent performance and durability of the catalyst were also investigated. The enhanced electrocatalytic activity of WS₂–MoS₂/NiMoP coatings increased with respect to the surface-active sites associated with combination of mixed dichalcogenides and the synergic effect arises in between different components present in the coating system. This work envisages the progressive strategies for the economical exploration of a novel WS₂–MoS₂/NiMoP water splitting catalyst used for large scale H₂ generation. The prepared WS₂–MoS₂/NiMoP embedded Cu substrate possess high catalytic activity due to its least overpotential of 101 mV at a benchmark current density of 10 mA cm^?2, which demonstrated the sustainable, efficient and promising electrocatalytic property of prepared catalyst towards HER under alkaline conditions.     

Porous Co2P film coated on carbon fiber as highly performance electrocatalyst toward overall water splitting

Designing porous active materials and enhancing their contact with conductive substrates is an effective strategy to improve electrolytic water splitting performance of noble metal-free catalysts. Herein, a facile nanostructured electrode, composed of porous Co₂P films coated on carbon fiber (CF@P–Co₂P), is designed and prepared. The unique three-dimensional interconnected pore structure of Co₂P and the close contact between porous Co₂P and CF not only increase specific surface areas to expose abundant catalytic sites but also stimulate the transport of electron, mass and gaseous products in catalytic process. Benefit from the reasonable electrode structure, the self-supported CF@P–Co₂P electrodes present perfect performance with only needing overpotentials of 107.7/175.5/141.8 mV for hydrogen evolution reaction (HER) in acidic/neutral/alkaline solution and 269.4 mV for oxygen evolution reaction (OER) in alkaline solution to get current density of 20 mA cm^?2. In addition, alkaline electrolyzer equipped with CF@P–Co₂P bifunctional electrodes only needs a cell voltage of 1.657 V to get water-splitting current density of 20 mA cm^?2. Even better, the electrolyzer can continuously electrolyze over 50 h with negligibly decreasing current density and the Faraday efficiency is close to 100% toward both HER and OER.     

Enhanced hydrogen evolution reaction of WS2–CoS2 heterostructure by synergistic effect

Transition metal dichalcogenides (TMDs) have attracted significant research interest due to its promising performance in hydrogen evolution reaction (HER). Synergistic effect between materials interface can improve the electrocatalytic properties. In this work, the WS₂–CoS₂ heterostructure supported on carbon paper (CP) was elaborately fabricated by a three-step method. Owing to the synergistic effect, WS₂–CoS₂ heterostructure exhibits an excellent electrocatalytic activity with a low overpotential of 245 mV at 100 mA/cm² and a small Tafel slope of 270 mV/dec toward HER. We demonstrate that the increased specific surface area and conductivity of the heterostructure play a key role in enhancing the overall catalytic efficiency. Moreover, the crystal lattice distortion in the heterostructure could induce charge redistribution and improve electron transfer efficiency, which may also benefit the whole HER activity.     

Vanadium doped cobalt phosphide nanorods array as a bifunctional electrode catalyst for efficient and stable overall water splitting

For the sake of sustainable development, water splitting without other pollutants has been a candidate technology in green energy. Due to the low efficiency of water splitting, innovative breakthroughs are desirable to improve efficiency significantly. Nowadays, the rational design of non-precious metal-based robust bifunctional catalysts is considered to be a feasible way to promote both the cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER). Herein, we proposed a vanadium doped CoP nanorods array catalyst grown on carbon cloth (V–CoP NRs/CC) as a bifunctional electrode material. When V–CoP NRs/CC employed as both anode and cathode materials, it only demands low cell voltages of 1.491 V and 1.606 V to drive a current density of 10 mA cm^?2 (j₁₀) and 50 mA cm^?2 (j₅₀) in 1 M KOH alkaline electrolyte. Especially, V–CoP NRs/CC can maintain its outstanding electrocatalytic performance for more than 40 h at j₅₀ in overall water splitting.     

Hierarchical flower-like CoS2-MoS2 heterostructure spheres as efficient bifunctional electrocatalyst for overall water splitting

Electrochemical water splitting technique requires high-efficient bifunctional electrocatalysts to obtain large-scale hydrogen production for resolving the impending energy and environmental crisis. Herein, hierarchical flower-like CoS₂-MoS₂ heterostructure hybrid spheres grown on carbon cloth (CoS₂-MoS₂/CC) were prepared by sulfuring wheel-shaped polyoxometalate {Co₂₀Mo₁₆}. The as-prepared CoS₂-MoS₂/CC as bifunctional electrocatalyst manifests excellent alkaline oxygen evolution and hydrogen evolution activities with low overpotentials of 240 mV for OER and 60 mV for HER at 10 mA cm^?2, respectively. When assembled as two-electrode cell, CoS₂-MoS₂/CC delivers an extremely low cell-voltage of 1.52 V at 10 mA cm^?2 accompanied with remarkable long-term durability. Additionally, CoS₂-MoS₂/CC exhibits favorable overall-water-splitting performance in simulated seawater. The superior performance of CoS₂-MoS₂/CC should be ascribed to the optimized intrinsic electron structure via electron transfer from MoS₂ to CoS₂ along with the synergistic effect of well-exposed heterostructure interfaces and favorable diffusion channels. This work offers a practical strategy for exploring high-efficient bifunctional electrocatalysts for overall water splitting.