NiS Nanoparticles Research Articles

Controllably solar-driven C‒C coupling organic synthesis integrated with H2 production over P-doped g-C3N4 with NiS nanoparticles modification

The development of mild and environmental method for direct transformation of aromatic alcohol into hydrobenzoin via controlled C‒C coupling is a highly attractive but challenging goal. In this paper, a P-doped g-C3N4 photocatalyst with NiS nanoparticles modification is first reported to apply the visible-light-driven C‒C coupling of aromatic alcohol into hydrobenzoin, as well as integrating with the production of clean H2 fuel. The synergistic effect of doped P atoms and formed type-II heterojunction between PCN and NiS improves the light absorption ability of g-C3N4 and greatly suppresses the charge recombination. Optimized 2.0% NiS/PCN composite achieves the complete conversion of aromatic alcohol within 6 h reaction time, as far as we known, which is the highest efficiency so far for aromatic alcohol conversion via photocatalytic strategy. Hydrobenzoin is controllably formed with 68% selectivity, together with a highly-efficient H2 production rate of 994.8 μmol·g−1·h−1. In-situ EPR studies reveal a preferential activation of C‒H bond than O‒H bond in aromatic alcohol by photoexcited holes, forming C6H5ĊH2OH radicals for subsequent coupling. The residual protons interact with photoexcited electrons to generate H2. Our study not only offers an efficient g-C3N4-based photocatalyst for the synthesis of hydrobenzoin under mild conditions, but also opens up a new avenue for manipulating the activation of C‒H or O‒H bonds for high selectivity of hydrobenzoin product.

Rationally designed hollow carbon nanospheres decorated with S,P co-doped NiSe2 nanoparticles for high-performance potassium-ion and lithium-ion batteries

Rationally designed hollow carbon nanospheres decorated with S,P co-doped NiSe2 nanoparticles for high-performance potassium-ion and lithium-ion batteries

MoS2/NiSe2/rGO Multiple-Interfaced Sandwich-like Nanostructures as Efficient Electrocatalysts for Overall Water Splitting

Constructing a heterogeneous interface using different components is one of the effective measures to achieve the bifunctionality of nanocatalysts, while synergistic interactions between multiple interfaces can further optimize the performance of single-interface nanocatalysts. The non-precious metal nanocatalysts MoS2/NiSe2/reduced graphene oxide (rGO) bilayer sandwich-like nanostructure with multiple well-defined interfaces is prepared by a simple hydrothermal method. MoS2 and rGO are layered nanostructures with clear boundaries, and the NiSe2 nanoparticles with uniform size are sandwiched between both layered nanostructures. This multiple-interfaced sandwich-like nanostructure is prominent in catalytic water splitting with low overpotential for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) and almost no degradation in performance after a 20 h long-term reaction. In order to simulate the actual overall water splitting process, the prepared nanostructures are assembled into MoS2/NiSe2/rGO||MoS2/NiSe2/rGO modified two-electrode system, whose overpotential is only 1.52 mV, even exceeded that of noble metal nanocatalyst (Pt/C||RuO2~1.63 mV). This work provides a feasible idea for constructing multi-interface bifunctional electrocatalysts using nanoparticle-doped bilayer-like nanostructures.

Fabrication of surface etched NiFe2O4-NiSe2 nanocomposite as an efficient electrocatalyst for oxygen evolution reaction

Investigating earth-abundant and potential electrocatalysts is pivotal for bringing electrochemical hydrogen production from laboratory production to an industrial scale. In this regard, nickel-based electrocatalysts are potential contenders for oxygen evolution reaction (OER) owing to their superior electrochemical activity and low cost. Herein, a nanocomposite made of NiFe2O4 and NiSe2 nanoparticles (20 nm) is reported for OER wherein a simple, new, and rapid wet chemical synthetic protocol is proposed. The experimental results reveal that the OER performance in the alkaline electrolyte is dependent on the etching rate of selenium. This is because the etching of surface selenium results in a mesoporous structure and a higher concentration of highly electroactive Ni3+ on the electrode surface. The 30 min etched NiFe2O4-NiSe2 nanocomposite exhibits 340 mV overpotential to realize a high current density of 100 mA cm−2 with a low Tafel slope of 52.1 mV dec-1. Additionally, as-synthesized NiFe2O4-NiSe2 nanocomposite shows stable performance over 75 h.

H-CoNiSe2/NC dodecahedral hollow structures for high-performance supercapacitors

The synergistic effect between metal ions and increasing the surface area leads to the fabrication of supercapacitor materials with high capacities. It is predicted that transition metal selenide compounds will be ideal electrode materials for supercapacitors. However, the defects of poor conductivity and volume expansion of the compounds are fundamental problems that must be solved. In this work, we successfully synthesized the cobalt–nickel selenide nitrogen-doped carbon (H-CoNiSe2/NC) hollow polyhedral composite structure using ZIF-67 as a precursor. The CoSe2 and NiSe2 nanoparticles embedded in the NC polyhedral framework offer a wealth of active sites for the whole electrode. Moreover, the presence of the NC structure in the proposed composite can simultaneously lead to improved conductivity and reduce the volume effect created during the cycling procedure. The H-CoNiSe2/NC electrode provides high specific capacity (1131 C/g at 1.0 A/g) and outstanding cyclic stability (90.2% retention after 6000 cycles). In addition, the H-CoNiSe2/NC//AC hybrid supercapacitor delivers ultrahigh energy density and power density (81.9 Wh/kg at 900 W/kg) and excellent cyclic stability (92.1% of the initial capacitance after 6000 cycles). This study will provide a supercapacitor electrode material with a high specific capacity for energy storage devices.Please confirm the corresponding affiliation for the 'Ali A. Ensafi' author is correctly identified.Error during converting author query response. Please check the eproofing link or feedback pdf for details

Nickel Chalcogenide Nanoparticles-Assisted Photothermal Solar Driven Membrane Distillation (PSDMD)

Developing photothermal solar driven membrane distillation (PSDMD) is of great importance in providing fresh water for remote off-grid regions. The production of freshwater through the PSDMD is driven by the temperature difference between feed and distillate sides created via the addition of efficient photothermal nanostructures. Here we proposed nickel sulfides and nickel tellurium nanoparticles (NPs) to be loaded into the polymeric membrane to enhance its performance. Ag and CuSe NPs are also considered for comparison as they are previously used for membrane distillation (MD). Our theoretical approach showed that all of the considered NPs increased the temperature of the PVDF membrane by around a few degrees. NiS and NiTe2 NPs are the most efficient solar light-to-heat converters compared to NiTe and NiS2 NPs due to their efficient absorption over the visible range. PVDF membrane loaded with 25% of NiCs NPs and a porosity of 32% produced a transmembrane vapor flux between 22 and 27 L/m2h under a 10-times-amplified sun intensity. Under the same conditions, the PVDF membrane loaded with CuSe and Ag NPs produced 15 and 18 L/m2h of vapor flux, respectively. The implantation of NPs through the membrane not only increased its surface temperature but also possessed a high porosity which provided a higher distillation and energy efficiency that reached 58% with NiS NPs. Finally, great agreement between our theoretical model and experimental measurement is obtained.

Coupling of NiSe2 with MoSe2 confined in nitrogen-doped carbon spheres as anodes for fast and durable sodium storage

On account of the relatively high theoretical capacity and lamellar structure, MoSe2 is considered as an advanced anode material applied for sodium-ion batteries (SIBs). Unfortunately, the notorious issues of MoSe2 including low electrical conductivity, tendency to restack and aggregate and high mechanical stress during cycling usually lead to the rapid deterioration of sodium storage properties. Herein, we propose the rational design and fabrication of NiSe2 nanoparticles decorated flower-like MoSe2 nanosheets simultaneously confined in N-doped carbon spheres (denoted as MoSe2-NC/NiSe2) via successive solvothermal and selenization steps. The heterostructure as generated between NiSe2 and MoSe2 can effectively provide more rich redox chemistry and synergistic merits. Meanwhile, the derived N-doped carbon matrix can protect the MoSe2 nanosheets from agglomeration, facilitate the electron transport in the composite, and accommodate the volume variation with the help of unique porous structure. Accordingly, the hybrid composite of MoSe2-NC/NiSe2 presents a high capacity of 315 mAh g−1 at 1 A g−1 and high-rate feature with 146 mAh g−1 even over 2000 cycles at 5 A g−1, demonstrating the excellent sodium storage performance including fast charging/discharging and outstanding cycling durability when applied in SIBs.

Core-shell NiS2@C encased by thin carbon layer as high-rate and durable electrode for aqueous rechargeable battery

Nickel sulfides, as promising candidate for aqueous rechargeable battery, have aroused broad attention on account of abundant natural resources, rich phases, moderate price and high theoretical capacity. Nevertheless, tremendous volume expansion during repeated charging-discharging procedure leads to the poor rate capability and cycling stability of nickel sulfide electrodes. Therefore, in this work, core–shell NiS2@C encapsulated by thin hydrothermal carbon (HC) layer (NiS2@C/HC) has been designed and prepared without any surfactants or templates assistance, which avoid tedious process and shorten preparation cycle greatly. When matched with the treated iron powder (TIP) electrode to form NiS2@C/HC//TIP aqueous rechargeable battery, the NiS2@C/HC//TIP battery exhibits a high discharge capacity of 205.1 mAh g−1 at 1 A g−1, remarkable rate ability (176.4 mAh g−1 at 5 A g−1, about 86% capacity conversation) and superiorly durable stability (80.8 % capacity retention after 10,000 cycles at ultra-high current density of 15 A g−1). The outstanding high-rate capability and cycling stability for aqueous rechargeable battery can be ascribed to the distinct cowpea-like architecture and intrinsic properties of NiS2@C/HC. Specifically, the interior porous carbon provides a space to tolerate the volume expansion of the NiS2 nanoparticles and prevent NiS2 nanoparticles from aggregation, guaranteeing its high-rate capability. Meanwhile, the exterior HC layer is conducive to improve the electric conductivity to facilitate the electrons transfer and promote the mechanical strength of the whole active materials, ensuring its robust cycling stability.

Ni3S2 nanoparticles encapsulated in S-doped biomass-derived hierarchically porous carbon as an advanced electrode for excellent hybrid supercapacitors performance

Although extensive efforts have been made to utilize raw biomass to synthesize porous carbon for the supercapacitor (SC), its large-scale application is difficult to achieve due to its slow diffusion kinetics and insufficient storage sites. Herein, biomass-derived high-capacity/high-rate cathode and anode materials are designed to realize high-performance SC. S-doped passionfruit peel-derived porous carbon (S-PFPC) is used as support to anchor nickel sulfide (Ni3S2) nanoparticles and is developed as cathode material. It provides sufficient sites to store discharge products, S-PFPC porous channels for fast electron transport, and uniformly dispersed Ni3S2 nanoparticles for enhance charge storage capacity. Simultaneously, hierarchically porous carbon with a high specific surface area as the anode material is also obtained by simple pyrolysis of passionfruit peel. Benefiting from the well-matched anode and cathode structures, the assembled Ni3S2 @S-PFPC//PFPC hybrid supercapacitor (HSC) exhibits a high energy density of 118 W h kg−1 at a power density of 433 W kg−1. In addition, it exhibits long-life stability with excellent capacitance retention of 88.3% over 10000 cycles. The route for preparing biomass-derived electrode materials proposed in this work broadens the horizon to realize high-performance SC applications.

Delaminated N-Ti3C2@Ni3S4 nanocomposites based high-performing supercapacitor device fabrication

In this research, we have made a breakthrough on the specific capacitance and cyclic stability of supercapacitors based on N-Ti3C2@Ni3S4 nanocomposites. These materials are prepared using in-situ growth of Ni3S4 nanoparticles on nitrogen doped delaminated Ti3C2 MXene via a hydrothermal method. The phase development and surface morphology are systematically investigated using a range of characterization techniques such as X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), and scanning electron microscopy (SEM). The electrochemical results demonstrate that N-Ti3C2@Ni3S4 nanocomposite has specific capacitance of 1280 Fg−1 at 1 Ag−1 current density, higher than d-Ti3C2 MXene, N-Ti3C2, Ti3C2@Ni3S4. N-Ti3C2@Ni3S4 showed 81% cyclic stability after 20,000 cycles. Furthermore, the symmetric supercapacitor (SSC) device of N-Ti3S4@Ni3S4 demonstrated an excellent energy density of 9.4 Wh kg−1 at a power density of 604 W kg−1 and 3 Wh kg−1 at 2016 W kg−1. N-Ti3C2@Ni3S4 nanocomposites for SSC device application make them advantageous for portable electronic devices.

Fabrication of noble-metal-free hierarchical rectangular tubular S-scheme NiS/ZnIn2S4/AgIn(WO4)2 nanocomposite for highly efficient photocatalytic hydrogen evolution

Accelerating the separation and transfer of photoinduced charge carriers is crucial for designing photocatalysts with superior photocatalytic hydrogen evolution (PHE) activity. Herein, a novel rectangular tubular hierarchical NiS/ZnIn2S4/AgIn(WO4)2 heterostructure was established by in-situ growing ZnIn2S4 nanosheets on the surface of tubular AgIn(WO4)2 and NiS nanoparticles (NPs) further deposited as co-catalysts for the first time. Based on the experimental and theoretical calculation results, the fabrication of ZnIn2S4/AgIn(WO4)2 S-scheme heterojunction as well as NiS NPs as active centers could account for the fast photogenerated charge carriers transfer and enhanced PHE activity. Notably, under simulated sunlight irradiation, the optimal NiS/ZnIn2S4/AgIn(WO4)2 composite exhibited a high PHE rate of 4818 µmol·g−1·h−1 without adding any noble-metal co-catalyst, which was about 24 and 3.7 times higher than that of pure AgIn(WO4)2 and ZnIn2S4, respectively. Meanwhile, the rate was up to 83 % of the value of ZnIn2S4/AgIn(WO4)2 with 3 wt% platinum (Pt) as co-catalyst, which meant that NiS NPs could replace Pt as an efficient noble-metal-free co-catalyst. This work provided a feasible approach to utilize the synergistic effect between co-catalyst and heterojunction for constructing efficient photocatalytic systems, and further confirmed the potential application of AgIn(WO4)2 with the special tubular morphology for PHE reaction.

Ambient ammonia synthesis via nitrite electroreduction over NiS2 nanoparticles-decorated TiO2 nanoribbon array

Nitrite (NO2−), as a N-containing pollutant, widely exists in aqueous solution, causing a series of environmental and health problems. Electrocatalytic NO2− reduction is a promising and sustainable strategy to remove NO2−, meanwhile, producing high value-added ammonia (NH3). But the NO2− reduction reaction (NO2−RR) involves complex 6-electron transfer process that requires high-efficiency electrocatalysts to accomplish NO2−-to-NH3 conversion. Herein, we report NiS2 nanoparticles decorated TiO2 nanoribbon array on titanium mesh (NiS2@TiO2/TM) as a fantastic NO2−RR electrocatalyst for ambient NH3 synthesis. When tested in NO2−-containing solution, NiS2@TiO2/TM achieves a satisfactory NH3 yield of 591.9 µmol h−1 cm−2 and a high Faradaic efficiency of 92.1 %. Besides, it shows remarkable stability during 12-h electrolysis test.

Interfacial Electronic Engineering of NiSe–Anchored Ni–N–C Composite Electrocatalyst for Efficient Hydrogen Evolution

Rational design and construction of cost–effective electrocatalysts for efficient hydrogen production has attracted extensive research attention worldwide. Herein, we report the construction of a transition metal selenide/carbon composite catalyst featuring uniform NiSe nanoparticles anchored to single Ni atom doped porous carbon structure (NiSe/Ni–N–C) via a facile one–pot pyrolysis of low–cost solid mixtures. NiSe/Ni–N–C exhibits remarkable catalytic performance towards hydrogen evolution reaction (HER) in 1.0 M KOH, requiring a low overpotential of 146 mV to reach a current density of 10 mA cm−2. The unique carbon layer encapsulation derived from the enwrapping of fluid catalytic cracking slurry further renders NiSe/Ni–N–C excellent for long–term durability in electrolyte corrosion and nanostructure aggregation. This work paves the way for the design and synthesis of highly efficient composite HER electrocatalysts.

NiSe2 Nanoparticles Supported on Halloysite Sheets as an Efficient Electrocatalyst toward Alkaline Oxygen Evolution Reaction

The oxygen evolution reaction (OER) with its sluggish kinetics has imposed a significant barrier to the sustainable and green generation of hydrogen fuel (via electrolysis of water) and the development of metal-air batteries. In this study, we report an efficient and novel OER electrocatalyst based on NiSe2 nanoparticles (NPs) and the naturally abundant halloysite clay mineral. The NiSe2/halloysite nanocomposite (NiSe2/H) was prepared by a simple one-step hydrothermal route. The electrocatalytic performance of the as-synthesized nanocomposite and its components (pristine NiSe2 and halloysite) toward OER in 1.0 KOH solution was examined. The NiSe2/H nanocomposite exhibited a significantly enhanced catalytic activity in OER, with a low overpotential of 235 mV (measured at the current density of 60 mA cm–2), a Tafel slope of 146 mV dec–1, and an outstanding long-term electrochemical durability for 16 h. Moreover, this nanocomposite required only 340 mV of overpotential to deliver the high current density of 250 mA cm–2. Further investigations revealed that the improved catalytic performance of NiSe2/H can be attributed to the increased number of active sites and the optimized adsorption energy of OH–. These results indicate that NiSe2/H is a promising non-precious metal-based catalyst for alkaline OER.

Atomic Heterointerface Engineering of Nickel Selenide Confined Nickel Molybdenum Nitride for High‐Performance Solar‐Driven Water Splitting

A heterostructured electrocatalyst of small NiSe2 nanoparticles confined NiMoN nanorods (NiSe2–NPs/NiMoN–NRs) is prepared to accelerate both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in a same alkaline medium. The synergistic effects caused by the combination of merits derived from NiSe2 and NiMoN phases trigger an optimum electronic structure with high density of state at near Fermi level and enhance adsorption free energy, thereby resulting in excellent catalytic activities and strengthened working stability. The catalyst requires a low overpotential of 58 mV for HER and 241 mV for OER to reach 10 mA cm−2 in 1.0 M KOH electrolyte. A two‐electrode electrolyzer based on the developed catalyst shows outstanding cell voltage of 1.51 and 1.46 V to reach 10 mA cm−2 in 1.0 M and 30 wt% KOH solution at 25 °C for overall water splitting, respectively. In addition, the solar‐driven water splitting process delivers a high solar‐to‐H2 conversion efficiency of ∼18.4%, impressively unveiling that the developed bifunctional catalyst is highly potential for overall water splitting to produce green hydrogen fuel.

A comparative study of structural, vibrational mode, optical and electrical properties of pure nickel selenide (NiSe) and Ce-doped NiSe nanoparticles for electronic device applications

Metal Chalcogenides have attracted considerable attention towards modern electronic device application due to their high abundance, high intrinsic conductivities, optical and electrical properties. Hence, a facile hydrothermal strategy is employed to synthesize pure NiSe and Ce-doped NiSe nanoparticles (NPs). Several characterization techniques are used to analyze the structural, Raman spectra, optical and electrical properties of the produced materials. The X-ray diffraction (XRD) investigations confirm the development of NiSe NPs and doping of Ce in the lattice of NiSe with a hexagonal nanocrystalline structure without any impurity phases. Raman spectra show the intensity of bands is enhanced with the enhancement in particle size due to increase in force constant and these Raman spectra consequences are well matched with XRD and confirm the purity and crystallinenature of the samples. Ultraviolet–visible spectroscopy is used to determine the optical properties. These demonstrations an increase and then decrease in the conduction band of NiSe NPs with the addition of Ce-content, i.e., from 1.92 eV to 1.98 eV and then 1.85 eV with the increase in Ce-content from 3% to 6%. This is endorsed for a high attraction between the metallic ions and the conduction electrons with the variation in particle size. The electrical studies reveal that the electrical characteristics of the prepared NPs improved with the substitution of Ce. The conductivity of the pure and Ce-doped NiSe NPs wasenhanced from 1.48 × 10−4to 8.01 × 10−3Ʊ cm−1 with the increase in Ce concentration up to 6%, while the resistivity was 6.75 × 103 to 1.25 × 102 Ωcm.The obtained consequences revealed that the doping the trace amount of Ce3+ improved the structural, vibrational mode, optical, and electrical properties of NiSe NPs.This means that the outcomes can be used for a large range of electronic applications.

Rational Design of NiSe/ReSe2 Nanocomposite For Efficient Electrochemical Hydrogen Evolution Reaction

The hydrogen evolution reaction (HER) in renewable energy systems has long been a fascinating process, but designing highly efficient and ultrastable electrocatalysts is challenging. Transition metal-based heterostructure nanohybrids are currently drawing more interest in the field of electrolysis because nanohybids can optimize kinetic processes while simultaneously lowering charge transfer resistance and increasing the electrochemically active electrode’s surface area at the reaction interface. Here, we propose a concept for a two-step colloidal hot injection electrocatalyst based on NiSe/ReSe2 nanocomposites that is extremely effective for hydrogen evolution under acidic conditions. The as-obtained nanocomposite material worked efficiently, attaining a current density of 10 mA cm−2 at a substantially lower over-potential of 120 mV vs RHE as compared to each of the individual components i.e. NiSe nanoparticles and ReSe2 nanosheets. As single component catalysts, ReSe2 nanosheets and NiSe nanoparticles, however, achieved current densities of 10 mA cm−2 at higher overpotentials of 172 mV and 221 mV, respectively. Even more intriguingly, the NiS/ReSe2 nanocomposite is believed to give a faster kinetic process for HER, as evidenced by a Tafel slope of 115 mV dec−1, which certainly is lower than that of the 179 mV dec−1 and 190 mV dec−1 for pure NiSe and ReSe2, respectively. NiSe nanocrystallites and ReSe2 nanosheets were assumed to be working in a synergistic manner to generate the electronic structural modification that led to the noticeably increased electrocatalytic properties. In order to make highly tuned electrocatalysts in solids, we anticipate that the fabrication of hybrid structures will be a successful strategy.

Remarkable photoelectrochemical activity of titanium dioxide nanorod arrays sensitized with transition metal sulfide nanoparticles for solar hydrogen production

The synthesis of a cost-effective and efficient catalyst is vital for accelerating the rate of photoelectrochemical hydrogen production. Here, titanium dioxide nanorods sensitized by nickel sulfide, cadmium sulfide, and zinc sulfide nanoparticles (ZnS/CdS/NiS@TiO2) were developed as a photoanode material via a hydrothermal process followed by the successive ionic layer adsorption and reaction. The morphological analysis of ZnS/CdS/NiS@TiO2 revealed the nanorods (TiO2) phase in which NiS, CdS, and ZnS nanoparticles are distributed homogeneously. The photoelectrochemical performance analysis of ZnS/CdS/NiS@TiO2 furnished a maximum photocurrent density of 6.1 mA/cm2, which is 7.6 times higher than that of pure TiO2 (0.8 mA/cm2). Additionally, the sensitized TiO2 nanorod arrays as a photoanode show high photoelectrochemical hydrogen production of 491.52 μmol/cm2, which is 4.9 times higher than that of pristine TiO2 (99.61 μmol/cm2) over 6 h under simulated solar irradiation. These results suggested the potential for the synthesis and usage of novel hybrids of TiO2 nanorods decorated with transition metal chalcogenides for efficient photoelectrochemical hydrogen production.

Fe-doped NiSe2 nanoparticles as efficient and stable electrocatalysts for oxygen evolution reaction

The application of electrocatalyst is the key to improve the efficiency of water splitting. Here, we report a Fe-doped NiSe2 catalyst prepared by a simple stirring method as a high-performance oxygen evolution reaction (OER) electrocatalyst in alkaline solutions. Utilizing synergistic effect between Fe and Ni, the Fe0.2Ni0.8Se2 catalyst exhibits excellent OER electrocatalytic activity and high stability in 1 M KOH solution, with the overpotential of 242 mV when the current density is 10 mA cm−2. As far as we know, this result is better than most of the nickel- based electrocatalysts reported.

Metal-organic framework derived ellipse-like NiS2 nanocatalyst for stable electrochemical hydrogen generation in alkaline electrolyte

The development of non-precious and high-efficient electrocatalysts to enhance the activity and stability in alkaline media is impending for massive hydrogen and oxygen production. In this study, NiS2 nanoparticles array with ellipse-like topography was fabricated via simple hydrothermal and sulfurization treatment. The NiS2-400 featured with the unique loose stacking topographic architecture contributes to more exposed active sites, the smaller contact resistance between electrode/electrolyte, faster ion diffusion and electron transfer. As a result, NiS2-400 electrode requires only overpotentials of 116 and 178 mV to drive current densities of 10 and 50 mA cm−2 in 1.0 M KOH towards the hydrogen evolution reaction (HER), coupled with a Tafel slope of 93.0 mV dec−1. Moreover, the resultant NiS2-400 nanoparticles exhibit excellent electrochemical stability for more than 50 h. In addition, the density functional theory (DFT) calculation further confirms that the (200) facet acts as the predominant active site, contributing to the enhanced HER performance.