Electrocatalytic Activity For Hydrogen Evolution Research Articles

Tailoring Electrocatalytic Hydrogen Evolution Activity in Topological Triangular Metal–Organic Frameworks

AbstractMetal–organic frameworks (MOFs) have attracted considerable attention in catalysis due to their exceptional structural and chemical tunability. However, high electrical conductivity is rare in MOFs, hindering their practical applications toward catalytic reactions. Recently, 2D topological MOFs stand out for the unique topologically nontrivial electronic structures. Particularly, their high electrical conductivity and chemical tunability make them promising candidates as high‐performance catalysts. In this study, theoretical investigations are conducted into the intrinsic electronic properties and chemical activity of a 2D topological Cu‐1,3,5‐tris(pyridyl)benzene (Cu‐TPyB) framework. It is found that the coordination environment of Cu with pyridyl groups plays a crucial role in modulating the electron density around the Fermi level, thereby enhancing the catalytic activity of Cu‐TPyB toward electrochemical hydrogen evolution reaction (HER). Furthermore, substituting the single embedded Cu atom with Cu3 and Cu4Bi3 clusters further increases the electron density around the Fermi level. Specifically, the Cu4Bi3‐TPyB framework exhibits superior HER activity, which is attributed to its high electron density contributed by the p orbitals of Bi and the d orbitals of Cu. This work introduces a novel approach for optimizing the catalytic activity of 2D MOFs and developing high‐performance catalysts.

U and Co Dual Single-Atom Doped MXene for Accelerating Electrocatalytic Hydrogen Evolution Activity.

A large amount of radioactive waste is accumulated in the process of nuclear fuel preparation, causing serious pollution to the environment and abundant depleted uranium resources to be abandoned. One of the key issues affecting the development of nuclear energy is how to make full use of depleted uranium resources efficiently. Here, U element with unique coordination mode of 5f electron is spacer bonded to transition metal with 3d orbit through the adsorption and anchoring effect of MXene, thus U and Co dual doped MXene catalyst is constructed along with the comprehensive utilization of depleted uranium resources. The as-prepared U-Co/MXene catalyst demonstrates excellent overpotential of only 184mV at -10mA cm-2 and excellent stability up to 150h, significantly surpassing the bare MXene substrate. Theoretical calculations indicate that the U and Co dual doping optimizes the electronic structure of MXene catalyst by forming the U-O-Co network, thereby improving the thermodynamics of H* adsorption during the catalytic transition state. This research opens up a new path for the recovery of depleted uranium resources and the development of functional actinide catalysts.

Vertical Conductive Metal-Organic Framework Single-Crystalline Nanowire Arrays for Efficient Electrocatalytic Hydrogen Evolution.

The construction of crystalline metal-organic frameworks with regular architectures supportive of enhanced mass transport and bubble diffusion is imperative for electrocatalytic applications; however, this poses a formidable challenge. Here, a method is presented that confines the growth of nano-architectures to the liquid-liquid interface. Using this method, vertically oriented single crystalline nanowire arrays of an Ag-benzenehexathiol (BHT) conductive metal-organic framework (MOF) are fabricated via an "in-plane self-limiting and out-of-plane epitaxial growth" mechanism. This material has excellent electrocatalytic features, including highly exposed active sites, intrinsically high electrical conductivity, and superhydrophilic and superaerophobic properties. Leveraging these advantages, the carefully designed material demonstrates superior electrocatalytic hydrogen evolution activity, resulting in a low Tafel slope of 66mVdec-1 and a low overpotential of 275mV at a high current density of 1Acm-2. Finite element analysis (FEA) and in situ microscopic verification indicates that the nanowire array structure significantly enhances the electrolyte transport kinetics and promotes the rapid release of gas bubbles. The findings highlight the potential of using MOF-based ordered nanoarray structures for advanced electrocatalytic applications.

Discovery of Self-Assembled 2D Ru/Si Superlattices Boosting Hydrogen Evolution.

2D heterostructuring is a versatile methodology for designing nanoarchitecture catalytic systems that allow for reconstruction and modulation of interfaces and electronic structures. However, catalysts with such structures are extremely scarce due to limited synthetic strategies. Here, a highly ordered 2D Ru/Si/Ru/Si… nano-heterostructures (RSHS) is reported by acid etching of the LaRuSi electride. RSHS shows a superior electrocatalytic activity for hydrogen evolution with an overpotential of 14mV at 10mA cm-2 in alkaline media. Both experimental analyses and first-principles calculations demonstrate that the electronic states of Ru can be tuned by strong interactions of the interfacial Ru-Si, leading to an optimized hydrogen adsorption energy. Moreover, due to the synergistic effect of Ru and Si, the energy barrier of water dissociation is significantly reduced. The well-organized superlattice structure will provide a paradigm for construction of efficient catalysts with tunable electronic states and dual active sites.

In-situ growth of MoSe2 on N-doped Ti3C2Tx for electrocatalytic hydrogen evolution in alkaline media

Abstract Serious environmental contamination and the energy crisis have heightened public desire for new renewable energy sources. Because of its high energy content and non-polluting qualities, hydrogen energy has emerged as a viable alternative to fossil fuels. Currently, high-purity hydrogen is typically produced through water electrolysis. The sensible use of electrocatalysts in this process can significantly minimize power usage in the electrolysis of water, which is of great significance to industrial production. However, the electrocatalyst that is inexpensive, has abundant reserves and performs well has yet to be discovered, severely restricting the promotion and application of hydrogen energy. In this paper, a MoSe2/N-doped Ti3C2TX heterostructure with notable electrocatalytic hydrogen evolution activity in an alkaline environment was fabricated via nitrogen doping and in-situ growth of molybdenum selenide. When the current density is 10 mA·cm-2, its overpotential and Tafel slope are 321.87 mV and 139.97 mV·dec-1, respectively. This work serves as a valuable experimental reference for the development of non-noble metal electrocatalysts based on two-dimensional materials.

An oxo‐acetato‐bridged trinuclear cobalt(III) cluster‐persuaded cobalt oxide active electrocatalyst for efficient hydrogen evolution activity

This study presents the synthesis and electrocatalytic performance of the cobalt(III) complex [Co3(μ1,1,1‐O)(μ1,3‐CH3CO2)(L)3]2(DMF)3 (Cotri), featuring a double deprotonated (N,O)‐donor ligand (L2‐), where the protonated form of it (H2L) is 2,2′‐(hydrazine‐1,2‐diylidenebis(ethan‐1‐yl‐1‐ylidene))diphenol. The X‐ray structure reveals a trinuclear cobalt cluster formed with three cobalt(III) centers interlinking through oxido (μ1,1,1‐O) and acetato (μ1,3‐O2CCH3) bridges in coupling with bis‐congregator‐type chelating ligands. Cotri adopts cobalt centers of octahedral and trigonal bipyramidal coordination geometries and bears a dominant Co(2)…H(DMF) agostic interactions appraised by lattice dimethyl formamide (DMF) molecules. Further, Cotri shows promising heterogeneous electrocatalytic hydrogen evolution activity in 1 M KOH, with an overpotential of 441 mV to achieve 10 mA/cm2 current density. Tafel slope analysis suggests the Volmer–Heyrovsky step as the rate‐determining step. The number of active sites and TOF for Cotri were estimated at 4.010 × 10−8 mol and 0.2467 s−1, respectively, ensuring its excellent hydrogen generation activity. Stability assessments through controlled potential electrolysis (CPE) and cyclic voltammetry (CV) for multiple cycles addressed the transformation of Cotri to Co2O3 nanoparticles, which turned out to be a more active Co2O3 electrocatalyst. The morphology and particle size of the in situ developed Co2O3 active catalyst under the electrochemical conditions attributes to the superior hydrogen evolution activity.

Ni-Substituted Sr2FeMoO6-δ as an Electrode Material for Symmetrical and Reversible Solid-Oxide Cells.

This work develops a novel perovskite Sr2FeNi0.35Mo0.65O6-δ (SFN0.35M) simultaneously using as a fuel electrode and oxygen electrode in a reversible solid oxide cell (RSOC). SFN0.35M shows outstanding electrocatalytic activity for hydrogen oxidation, hydrogen evolution, oxygen reduction, and oxygen evolution. In situ exsolution and dissolution of Fe-Ni alloy nanoparticles in SFN0.35M is revealed. In a reducing atmosphere, SFN0.35M shows in situ exsolution of Fe-Ni alloy nanoparticles, and then the Fe-Ni alloy is reoxidized into SFN0.35M while converting into an oxidizing atmosphere. The polarization resistances of SFN0.35M electrode are 0.043 Ω cm2 in 20% O2-N2 and 0.064 Ω cm2 in H2 at 850 °C. Moreover, symmetric fuel cells using the SFN0.35M electrode achieves a maximum power density of 0.501 W cm-2 at 850 °C in H2 fuel, while the symmetric electrolysis cell has an electrolysis current density of 0.794 A cm-2 at 1.29 V in 90% H2O-10% H2 at 850 °C. It is the first time we demonstrate that the cell voltage of symmetrical cell at 0.5 A cm-2 in the fuel cell mode and -0.5 A cm-2 in the electrolysis cell mode can be fully recovered in 10 electrode alternating cycles and therefore demonstrate the possibility that SFN0.35M can be used in a fully symmetric RSOC stack with electrode alternating functions.

Top-down nanostructured multilayer MoS2 with atomically sharp edges for electrochemical hydrogen evolution reaction

Cost-efficient and readily scalable platinum-free electrocatalysts are crucial for a smooth transition to future renewable energy systems. Top-down activation of MoS2 promises the production of sustainable hydrogen evolution electrocatalysts from the Earth-abundant molybdenite ore. Here, the deterministic nanopatterning of multilayer MoS2 with numerous zigzag edges is explored as a pathway to enhance hydrogen evolution reaction (HER). Nanopatterned single-nanosheet MoS2 electrodes are assessed by two highly localized electrochemical techniques: selected area voltammetry (with lithography-defined regions of electrode-electrolyte contact) and Scanning ElectroChemical Microscopy (SECM). The nanopatterning effect is the most pronounced after prolonged electrochemical cycling in an acidic electrolyte. The electrocatalytic hydrogen evolution activity of edge-enriched electrodes is dramatically enhanced: the maximum electrochemical current density (jmax) achieved at -510 mV vs. reversible hydrogen electrode (mVRHE) is increased by two orders of magnitude, reaching >300 mA⋅cm−2. Both the η10 and η100 overpotentials are significantly reduced as well. Meanwhile, pristine MoS2 shows just ≈6 times jmax increase (≈30 mA⋅cm−2) after the very same cycling. The increased electrocatalytic activity comes with electrode morphology degradation, evidenced by ex-situ scanning electron microscopy. SECM directly visualizes stronger HER activity in the regions with densely located zigzag edges. Intense white light illumination significantly boosts HER on MoS2 electrodes due to the photo-enhanced MoS2 conductivity. These results improve the understanding and reveal the limitations of MoS2-based electrocatalytic water splitting.

Electrocatalytic hydrogen evolution by cobalt(Ⅲ) triphenyl corrole bearing different number of trifluoromethyl groups

Hydrogen production from electrolyzing water is known as the most promising hydrogen production method. To further understand the effect of steric hindrance and electron-withdrawing groups on catalysts, four cobalt triphenyl corroles bearing different number of ortho-trifluoromethyls (1, 2, 3, 4) had been synthesized and used as hydrogen evolution electrocatalysts. These cobalt corroles showed effective electrocatalytic hydrogen evolution activity in organic medium and neutral aqueous medium, with turnover frequency ranging from 100 s−1 to 220 s−1 using 32 equivalents of trifluoroacetic acid proton source in DMF. The electrocatalytic HER goes via competitive ECEC or EECC pathway depending on the used proton source. The electrocatalytic HER activity varies obviously with the number of the peripheral ortho- groups. This work is helpful for the design of new metal corrole HER electrocatalyst.

Insitu formation of low-valence state cobalt cation in octahedral sites of Co9S8 for highly efficient electrocatalytic hydrogen evolution

The elementary valence state in electrocatalysts has been demonstrated to significantly affect their catalytic ability. However, enhancing performance by controlling the elemental valence state and the precise doping location remains challenging. This work is devoted to exploring a controllable electronic structure that is capable of improving electrocatalytic hydrogen evolution activity by manipulating the valence state of an element at a specific location. This is demonstrated by reducing the high valence state Co3+ in octahedral sites of Co9S8 to form low valence state Co2+ using sodium borohydride. The occupation of Co2+ in the Co3+ site gives rise to the generation of local lattice distortion, which provides more efficient active sites for the hydrogen evolution reaction (HER). Additionally, Co2+ in octahedral sites donates more electrons to adsorbed water molecules, which facilitates HO–H dissociation and H∗ adsorption. The resulting electrocatalyst exhibits a low overpotential of 301 mV at 500 mA/cm2 for the HER, which is the best performance among all reported single-component Co9S8-based catalysts. This work paves an avenue for the rational design of HER electrocatalysts by precisely tuning the valence state of elements at specific locations.

Size-dependent electrocatalytic hydrogen evolution activity of arrays of edge-like defects in MoS2 crystals patterned by focused ion beam

Introducing surface defects on molybdenum disulfide (MoS2) crystals plays a crucial role in enhancing the electrocatalytic activity toward the hydrogen evolution reaction (HER). Despite the remarkable progress in this area,...

Superior electrocatalytic hydrogen evolution activity of a triply bridged diruthenium(II) complex on a carbon cloth support.

This article describes the structural authentication of a unique triply bridged [1](ClO4)2 and monomeric [2]ClO4/[3]ClO4. Electrochemical HER on a carbon cloth support demonstrated the superior performance of [1](ClO4)2 with high TON (>105) and its long-term stability. The primary kinetic isotope effect of [1](ClO4)2 revealed the involvement of PCET in the rate-determining step.

Axial ligand-induced high electrocatalytic hydrogen evolution activity of molecular cobaloximes in homo- and heterogeneous medium.

Three new molecular cobaloxime complexes with the general formula [ClCo(dpgH)2L] (1-3), where L1 = N-(4-pyridylmethyl)-1,8-naphthalimide, L2 = 4-bromo-N-(4-pyridylmethyl)-1,8-naphthalimide, L3 = 4-piperidin-N-(4-pyridylmethyl)-1,8-naphthalimide, have been synthesized and characterized by UV-Vis, multinuclear NMR, FT-IR and PXRD spectroscopic techniques. The crystal structures of all complexes have also been reported. The electrocatalytic activity of complexes is investigated under two catalysis conditions: (i) homogeneous conditions in acetonitrile using acetic acid (AcOH) as a proton source and (ii) heterogeneous conditions upon immobilization onto the surface of activated carbon cloth (CC). Complex 3 exhibited high electrocatalytic HER activity under both homogeneous and heterogeneous conditions. It catalyses proton reduction to molecular hydrogen in acetonitrile solution at a lower overpotential (640 mV) with a high turnover frequency (TOF) of 524.57 s-1 and demonstrates good stability in acidic conditions. Furthermore, catalytic (working) electrodes are prepared by immobilizing the complexes onto the surface of activated carbon cloth (CC) for electrocatalytic HER under heterogeneous conditions. An impressive HER performance was again obtained with catalytic electrode 3@CC in 1.0 M KOH, achieving a current density of -10 mA cm-2 at an overpotential of 262 mV. Chronoamperometric (CA) studies showed no significant decay of the initial current density for 10 h, indicating the excellent stability of 3@CC. Additionally, UV-Vis and NMR spectral studies of the recovered catalyst after electrocatalysis revealed no structural changes, demonstrating its robustness under reaction conditions.

Electron transfer at the heterojunction interface of CoP/MoS2 for efficient electrocatalytic hydrogen evolution reaction.

Modulating the electronic states of electrocatalysts is critical for achieving efficient hydrogen evolution reaction (HER). However, how to develop electrocatalysts with superior electronic states is an urgent challenge that must be addressed. Herein, we prepared the CoP/MoS2 heterojunction with a microsphere morphology consisting of thin nanosheets using a facile two-step method. The catalyst's ultrathin nanosheet structure not only provides an extensive surface area for exposing active sites, but it also enables ion transport and bubble release. Electron transfer occurs between CoP and MoS2, optimizing the heterojunction's charge distribution and enhancing the intermediates' adsorption capabilities. As a result, the CoP/MoS2 heterojunction exhibits outstanding electrocatalytic hydrogen evolution activity with an overpotential of only 88 mV at a current density of 10 mA cm-2, which exceeds both the sulfide heterojunction Co9S8/MoS2 and the phosphide heterojunction CoP/CoMoP2. The experimental results and DFT calculation results show that the former has stronger synergistic effects and higher HER activity. This work sheds light on the exploration of efficient heterojunction electrocatalysts with excellent electronic structures.

Modulating the electronic structure of VS2via Ru decoration for an efficient pH-universal electrocatalytic hydrogen evolution reaction.

High-efficiency water electrolysis over a broad pH range is desirable but challenging. Herein, Ru-decorated VS2 on carbon cloth (Ru-VS2/CC) has been in situ synthesized, which features the regulated electronic structure of VS2 by introducing Ru. It is remarkable that the optimal Ru-VS2/CC displays excellent electrocatalytic hydrogen evolution activity with overpotentials of 89 and 87 mV at -10 mA cm-2 in 0.5 M H2SO4 and 1.0 M KOH, respectively. Theoretical calculations and electrocatalytic measurements have demonstrated that introducing Ru induces an enhanced charge density around the Fermi level, facilitating charge transfer and speeding up the electrocatalytic HER kinetics. The Gibbs free energy of the hydrogen intermediate (ΔGH*) of Ru-VS2/CC (0.23 eV) is much closer to zero than that of pure VS2 (0.51 eV) and Ru (-0.37 eV), demonstrating an easier hydrogen adsorption and desorption process for Ru-VS2/CC. The more favorable ΔGH*, differential charge density and the d-band center endow Ru-VS2 with enhanced intrinsic electrocatalytic activity. This study presents a feasible strategy for enhancing electrocatalytic HER activity by the regulation of the electronic structure and the rational integration of dual active components.

Defective Biphenylene as High-Efficiency Hydrogen Evolution Catalysts.

Electrocatalysts play a pivotal role in advancing the application of water splitting for hydrogen production. This research unveils the potential of defective biphenylenes as high-efficiency catalysts for the hydrogen evolution reaction. Using first-principles simulations, we systematically investigated the structure, stability, and catalytic performance of defective biphenylenes. Our findings unveil that defect engineering significantly enhances the electrocatalytic activity for hydrogen evolution. Specifically, biphenylene with a double-vacancy defect exhibits an outstanding Gibbs free energy of -0.08 eV, surpassing that of Pt, accompanied by a remarkable exchange current density of -3.08 A cm-2, also surpassing that of Pt. Furthermore, we find the preference for the Volmer-Heyrovsky mechanism in the hydrogen evolution reaction, with a low energy barrier of 0.80 eV. This research provides a promising avenue for developing novel metal-free electrocatalysts for water splitting with earth-abundant carbon elements, making a significant step toward sustainable hydrogen production.

Effective electrocatalytic hydrogen evolution of carbon paste electrode modified by Fe (II) and Ni (II) phenylimidazole‐dicarboxylate complexes

The structure determined is helpful to explore the reaction mechanism and provide a design strategy for the synthesis of high‐performance hydrogen evolution reaction (HER) electricity catalysts. Therefore, two structurally tunable and deterministic metal complexes, [Fe(m‐H2MOPhIDC)2(H2O)2]·2H2O (1) and [Ni(m‐HMOPhIDC)(H2O)2)]n (2) (m‐H3MOPhIDC = 2‐[3‐methoxyphenyl]‐1H‐imidazole‐4,5‐dicarboxylic acid), were synthesized under solvothermal conditions and used to assemble modified carbon paste electrodes (CPE 1–2) to explore the relationship between structure and catalytic performance. Structural analysis revealed that complexes 1 and 2 had a mononuclear structure and 1D linear structure, respectively, and that the central ions of the two complexes had the same coordination environment of the octahedral spatial configuration. In 0.5 M H2SO4 and 293 K, linear sweep voltammetry and Tafel curve indicate that the η10 (overpotential, 10 mA cm−2) of two modified carbon paste electrodes are −574 and −539 mV and Tafel slopes are 161 and 128 mV dec−1. Comparing the overpotential of CPE 1–2 with that of unmodified solid carbon paste electrode (sCPE, −976 mV), it was found that the overpotential of CPE1–2 shifted positively and the Tafel slopes are obviously reduced compared to sCPE (221 mV dec−1), which proves that the CPE 1–2 has effective electrocatalytic hydrogen evolution activity. The controlled potential electrolysis and impedance spectroscopy further validated the above conclusions. The higher HER activity of the CPE 2 than CPE 1 can be attributed to the fact that complex 2 is a one‐dimensional polymer, which can efficiently disperse the catalytic active site. The use of metal complexes as HER electrocatalysts provides a new idea for an effective method for converting electric energy into hydrogen energy and is beneficial to the development of the HER research field.

(Cu3-x Nix)Co2-Layered Double Hydroxide Nanosheets for Enhanced Electrocatalytic Activity Towards Overall Water Splitting

The exploration of transition metal based electrocatalyst for overall water splitting is becoming important as hydrogen becomes integral part of energy landscape. Recently, a new class of compounds i.e. layered double-hydroxides (LDHs), also known as anionic clays, are have shown tremendous promise for use as electrocatalyst. The lamellar morphology of LDHs accommodates higher active sites, that contributes to the facile electron transfer and thus attracts a great deal of interest in catalysis application. Moreover, the high catalytic activity of LDHs are also linked to their facile anion exchange, specific electronic structures, and versatile chemical compositions.Herein, we have developed a series of ternary layered double hydroxide (LDH) using pH-adjusted co-precipitation method with varying ratio of Cu, Ni and Co, which are used as an electrocatalyst for overall water splitting. (CuxNi1)Co1-LDHs (x = 0.5 1, 1.5, and 2 ) were systematically characterized using XRD, XPS, SEM, FTIR, TEM and BET techniques. The synergistic contributions from the electrocatalytically active metals and lamellar morphology of LDHs promotes water dissociation, facilitates faster release of H2-O2 gas bubbles, ameliorate electrolyte ion diffusion and improves electron transfer rate. It is further observed that the (CuxNi1)Co1-LDHs showed excellent electrocatalytic activity for both hydrogen evolution (HER) and oxygen evolution reaction (OER) with an overpotential of 147 and 218 mV for HER and OER, respectively at 10 mA cm-2. Tafel slope was found to be lowest for (Cu1Ni1)Co1-LDH. Further, the durability of the materials was also analysed by performing chronoamperometry for over 12 h. The overall water electrolytic cell using (Cu1Ni1)Co1-LDH as both electrodes can reach 50 mA cm−2 at 1.9V with outstanding durability.

Ultrafine Pt NanoparticlesAnchored on 2D Metal-Organic Frameworks as Multifunctional Electrocatalysts for Water Electrolysis and Zinc-Air Batteries.

Multifunctional electrocatalysts are crucial to cost-effective electrochemical energy conversion and storage systems requiring mutual enhancement of disparate reactions. Embedding noble metal nanoparticles in 2D metal-organic frameworks (MOFs) are proposed as an effective strategy, however, the hybrids usually suffer from poor electrochemical performance and electrical conductivity in operating conditions. Herein, ultrafine Pt nanoparticles strongly anchored on thiophenedicarboxylate acid based 2D Fe-MOF nanobelt arrays (Pt@Fe-MOF) are fabricated, allowing sufficient exposure of active sites with superior trifunctional electrocatalytic activity for hydrogen evolution, oxygen evolution, and oxygen reduction reactions. The interfacial Fe─O─Pt bonds can induce the charge redistribution of metal centers, leading to the optimization of adsorption energy for reaction intermediates, while the dispersibility of ultrafine Pt nanoparticles contributes to the high mass activity. When Pt@Fe-MOF is used as bifunctional catalysts for water-splitting, a low voltage of 1.65V is required at 100mA cm-2 with long-term stability for 20h at temperatures (65°C) relevant for industrial applications, outperforming commercial benchmarks. Furthermore, liquid Zn-air batteries with Pt@Fe-MOF in cathodes deliver high open-circuit voltages (1.397V) and decent cycling stability, which motivates the fabrication of flexible quasisolid-state rechargeable Zn-air batteries with remarkable performance.

Reversible active bridging sulfur sites grafted on Ni3S2 nanobelt arrays for efficient hydrogen evolution reaction

Elaborate and rational design of cost-effective and high-efficiency non-noble metal electrocatalysts for pushing forward the sustainable hydrogen fuel production is of great significance. Herein, a novel VS4 nanoparticle decorated Ni3S2 nanobelt array in-situ grown on nickel foam (VS4/Ni3S2/NF NBs) was prepared by a self-templated synthesis strategy. Benefitting from the unique nanobelt array structure, abundant highly active bridge S22- sites and strong electronic interaction between VS4 and Ni3S2 on the heterointerface, the integrated VS4/Ni3S2/NF NBs exhibited excellent electrocatalytic hydrogen evolution activity and robust stability. The density functional theory (DFT) further revealed the reversible conversion catalysis mechanism of bridging S22- sites in VS4/Ni3S2/NF NBs during HER process. Notably, bidentate bridging SS bonds as the predominant catalytically active centers can spontaneously open once H adsorbed its surface, leading to the aggregation of negative charges on S atoms and thus facilitating the generation of H* intermediates, and spontaneously close when H* desorption is going to form H2. Our work provides fresh insights for developing potential polysulfides as high-performance hydrogen-evolving electrocatalysts for prospective clean energy production from water splitting.