Ni3S2 Nanosheet Arrays Research Articles

Synchronously integration of carbon-quantum-dot and Cu, Mo dual-metal doped in Ni3S2@Ni foam toward robust and stable electrocatalytic hydrogen generation

In the pursuit of advancing the production of H2 through hydrogen-evolution reaction (HER), the demand for the elaborate design of cost-effective and robust durability electrocatalysts has gained momentum, especially replacement of noble-metal counterparts like Pt. Herein, we introduce a facile one-pot hydrothermal approach to synthesize nickel foam-supported Ni3S2 nanosheet arrays, which integrate with carbon-quantum-dot (CQDs) and Cu, Mo dual-metal doped. With the introduction of CQDs and Cu, Mo dual-metal doped site, the optimal CQDs-Cu-Mo-Ni3S2@NF exhibits superior HER catalytic activity with a low overpotential of 125 mV at 10 mA·cm−2 and strong durability for 30 h in alkaline medium. The exceptional electrocatalytic performance is ascribed to the synergistic effect of CQDs and Cu, Mo dual-metal site. This synergy encompasses optimization of water molecule adsorption/desorption energetics, elevated electrical conductivity, weakening of the strong S–H bond interaction on the Ni3S2 surface, and providing ample active centers. Furthermore, an in-depth understanding of the electronic structure and adsorption energy during the HER process is probed by density functional theory (DFT) analysis. Our work provides a quintessential paradigm for the rational design of multi-component electrocatalysts for water splitting.

Photothermal-regulated selective desorption of enantiomers from Ag/Ni3S2 nanosheet-covered Ni foam

Separation of racemates is critically important in the chemical, agrochemical and pharmaceutical industries, since enantiomers may differ in biological interactions, pharmacology, and toxicity. However, the methods for highly enantioselective separation are still insufficient. In this study, we prepared Ni3S2 nanosheet arrays with excellent photothermal properties using Ni foam as the precursor. The PT enantioselective desorption approach is based on a Ni3S2 NSA decorated with Ag nanoparticles modified with D-penicillamine as the enantioselective substrate. Finite-difference time-domain simulation was used to probe the optimal number, shape, and distribution of Ag NP to optimize the localized surface plasmon resonance and photothermal effect. The enantiomers of 3,4-dihydroxyphenylalanine were used as models to demonstrate enantioselective separation based on the different number of stable hydrogen bonds between the homochiral substrate and each enantiomer. This enantioselective desorption approach has the advantages of efficiency, low cost, and recyclability, and provides a new solution for separating racemic molecules.

Fe, Mn-Ni3S2 directly grown on nickel foam as an environmentally friendly electrocatalyst for seawater splitting

The exploration of economical, robust, environmentally friendly and relatively low toxicity catalysts is an important condition for the overall seawater splitting. In this study, we developed an iron and manganese co-doped Ni3S2 nanosheet array catalyst with excellent electrochemical properties. Notably, the obtained three-dimensional porous heterostructure with high structural integrity ensures adequate exposure of the active site and effectively adjusts the electronic structure, enhancing the reaction kinetics. Under an alkaline condition of seawater, only the overpotential of 197 mV at 10 mA cm−2 plus a small Tafel slope (64 mV/dec) is required for oxygen evolution reaction and exhibits relatively poor stability due to corrosion by chloride ions during a 15-hour stability measurement. Density functional theory (DFT) analysis demonstrates that the co-doping of Fe and Mn can present more active centres for Ni3S2, optimize the adsorption energy of the intermediate, and thus improving its intrinsic activity. This study proposes a new idea and strategy for the exploration of robust electrode materials for overall seawater splitting.

Mo-doped Ni3S2 nanosheet arrays for boosting hydrogen evolution activity and supercapacitor energy storage

The design and preparation of bifunctional electrode materials play a vital role in the field of energy storage and conversion. Herein, Mo-doped Ni3S2 nanosheet arrays assembled on nickel foam (named as Mo-Ni3S2) are designed through three-step continuous hydrothermal methods for enhanced hydrogen evolution reaction (HER) and supercapacitor storage characteristics. The ultrathin Mo-Ni3S2 nanosheets structure could modulate electronic structure and offer rich actives sites, thereby expediting the mobility of charge carriers and engendering a greater density of active sites. Consequently, the Mo-Ni3S2 exhibits low overpotential both in alkaline and acidic solution with the value of 53 and 65 mV at the current density of 10 mA cm−2, respectively. Meanwhile, the HER activity can be well maintained after 17 h of continuous operation at 10 mA cm−2, demonstrating its excellent stability. Furthermore, the as-prepared Mo-Ni3S2 as pseudocapacitive materials exhibits a specific capacitance of 3528 F g−1 at 1 A g−1, implying outstanding long durability with 96.5% capacity retention after 3000 charge–discharge cycles. Overall, this work provides a viable strategy for the development of transition metal-based materials as efficient bifunctional catalysts.

Co-doped Ni3S2 nanosheet array: A high-efficiency electrocatalyst for alkaline seawater oxidation

Co-doped Ni3S2 nanosheet array: A high-efficiency electrocatalyst for alkaline seawater oxidation

Cd doped Ni3S2 nanosheet arrays grown on nickel foam as highly efficient and robust bifunctional electrocatalysts for alkaline overall water splitting

Stable and highly efficient electrocatalysts are very important for water splitting. Introducing exogenous elements can alter the structure of the catalysts, thus improving the electrocatalytic activity. In this study, via a facile hydrothermal strategy and Cd/Ni ratio tuning, Cd-doped Ni3S2 nanosheet arrays grown on Ni foam (Cd-Ni3S2/NF-x) are fabricated. The optimized Cd-Ni3S2/NF-1/4 exhibits the best electrocatalytic performance in alkaline media (1 M KOH) due to the higher electroconductivity and more accessible active sites. At a current density of 10 mA cm-2, ultralow overpotentials of 140 and 197 mV are required for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. During overall water splitting, a two-electrode electrolyzer of Cd-Ni3S2/NF-1/4 was used to achieve a low cell voltage of 1.54 V with ultralong-term durability ≥ 50 h. Introducing Cd into Ni3S2 leads to Ni→S electron transfer, thus increasing the Ni3+ content, which is beneficial to the increased OER activity. Density functional theory (DFT) calculations demonstrate that Cd-doped Ni3S2 has a reduced Gibbs free energy of hydrogen adsorption (∆GH*) in the HER and a decreased energy barrier of rate determination in the OER, contributing to the improved overall water-spitting performance. This work offers an effective strategy by virtue of element doping to fabricate highly effective bifunctional electrocatalysts to realize mass production of hydrogen.

Plasma-modified iron-doped Ni3S2 nanosheet arrays as efficient electrocatalysts for hydrogen evolution reaction

The development of efficient transition-metal catalysts for the hydrogen evolution reaction is significant to meeting global energy demands. In this study, to realize a high-performance electrocatalyst, we synthesize an Fe-doped Ni3S2 nanosheet material in situ on 3D structured nickel foam via the hydrothermal sulfide method, and then modify it by the dielectric barrier discharge plasma technique. Combining Fe atom doping and plasma modification increases the electrochemical surface area, provides an abundance of active sites, optimizes the electronic structure, and accelerates the reaction kinetics, thereby improving catalytic activity. As a result, the PA@Fe1/4-Ni3S2/NF catalyst exhibits excellent hydrogen evolution reaction activity, only requires ultra-low overpotentials to achieve a current density of 10 mA cm−2, and exhibits excellent durability. This study proposes a novel method for rationally designing non-noble metal electrocatalysts.

Hierarchically porous nickel foam supported Fe-Ni3S2 electrode for high-current–density alkaline water splitting

Alkaline water electrolysis (AWE) offers a promising route for green hydrogen production. However, its industrial application is impeded by unsatisfactory energy conversion efficiency. Herein, a robust electrode composed of porous nickel foam (PNF) and Fe-doped Ni3S2 (Fe-Ni3S2) nanosheet arrays was fabricated and applied for industrial AWE. By conducting a scalable dynamic bubble-template method, PNF with high loading of active catalysts was prepared. The superhydrophilicity of PNF facilitates bubble detachment and promotes mass transfer, especially at high current densities. In addition, Fe-Ni3S2 with optimized electronic structure is featured with enhanced electrical conductivity, sufficient exposure of active sites, and optimized adsorption of intermediates. Benefiting from the concerted advantages of PNF and Fe-Ni3S2, the obtained Fe-Ni3S2/PNF-5 electrode with an optimal Fe content of 5 mol% exhibits high catalytic activity for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Compared with the Pt/C/NF||IrO2/NF couple, the Fe-Ni3S2/PNF-5||Fe-Ni3S2/PNF-5 couple delivers a current density of 10 mA cm−2 at a low cell voltage of 1.50 V for AWE. Under industrial conditions, a competitive cell voltage of 1.75 V is needed for achieving a high current density of 400 mA cm−2. Besides, the couple can operate stably for 120 h, outperforming the commercial RN||RN couple. This work provides a novel strategy to elevate the loading amount of catalysts and improve the electrochemical performance of the electrode for practical AWE application.

Facile synthesis of self support Fe doped Ni3S2 nanosheet arrays for high performance alkaline oxygen evolution

• Fe doped Ni 3 S 2 /NF were prepared via a facile hydrothermal method. • The OER performance of Ni 3 S 2 /NF was significantly enhanced after Fe doping. • A small PDS for doped Ni 3 S 2 /NF of 0.31 eV can be obtained at the Fe site. Transition metal sulfides are one of the most efficient earth-abundant oxygen evolution reaction (OER) electrocatalysts. In the present study, Fe doped Ni 3 S 2 nanosheets have been directly grown on nickel foam via a facile hydrothermal process. The OER electrocatalytic activity of Fe-Ni 3 S 2 /NF can be enhanced by adjusting the addition amount of Fe. It requires an overpotential of 246 mV to afford a current density of 20 mA cm −2 and a Tafel slope of 66 mV dec −1 , significantly lower than that of Ni 3 S 2 /NF electrode. This catalyst is highly stable, showing a slight overpotential rise of 15.1 mV over continuous testing for 20 h. In addition, combine EIS measurement and density functional theory calculations, revealing that Fe doped Ni 3 S 2 /Ni electrodes have both high conductivity and excellent intrinsic activity, leading to a promising OER electrocatalytic activity.

Cd Doped Ni3s2nanosheet Arrays Grown on Nickel Foam as Highly Efficient and Robust Bifunctional Electrocatalysts for Alkaline Overall Water Splitting

Cd Doped Ni3s2nanosheet Arrays Grown on Nickel Foam as Highly Efficient and Robust Bifunctional Electrocatalysts for Alkaline Overall Water Splitting

Fe Doped Ni3S2 Nanosheet Arrays for Efficient and Stable Electrocatalytic Overall Urea Splitting

Fe Doped Ni₃S₂ Nanosheet Arrays for Efficient and Stable Electrocatalytic Overall Urea Splitting

Controllable 3D Porous Ni Current Collector Coupled with Surface Phosphorization Enhances Na Storage of Ni3 S2 Nanosheet Arrays.

3D porous Ni is fabricated via an easily scalable electroless plating method using a dynamic template formed through in-situ hydrogen bubbles. The pore size in the range of several micrometers is controllable through adjusting the Ni2+ depositing rate and hydrogen bubbles releasing rate. The Ni3 S2 nanosheet arrays anode is then grown on the unique 3D porous Ni current collector followed by subsequent surface phosphorization. The tremendous interconnected pores and rich voids between the Ni3 S2 nanosheet arrays cannot only provide rapid transferring channels for Na+ , but also accommodate volumetric changes of the Ni3 S2 electrode during cycling, guaranteeing the integrity of the active material. In addition, the surface phosphorized layer enhances the electronic conductivity through providing an electron transport highway along the 3D Ni3 S2 , NiP2 layer, and 3D porous Ni current collector, and simultaneously stabilizes the electrode/electrolyte interphase as a protecting layer. Because of these merits, the phosphorized 3D porous Ni3 S2 (3D P-Ni3 S2 ) electrode is capable of delivering an ultra-stable capacity of 387.5 mAh g-1 at 0.1 A g-1 , and a high capacity retention of 85.3% even at a high current density of 1.6 A g-1 .

Hierarchical Ni3S2 nanorod@nanosheet arrays on Ni foam for high-performance supercapacitor

We successfully designed and prepared hierarchical Ni3S2 nanorod@nanosheet arrays on three-dimensional Ni foam via facile hydrothermal sulfuration. We conducted a series of time- and temperature-dependent experiments to determine the Ostwald ripening process of hierarchical Ni3S2 nanorod@nanosheet arrays. The rationally hierarchical architecture creates an excellent supercapacitor electrode for Ni3S2 nanorod@nanosheet arrays. The areal capacitance of this array reaches 5.5 F cm−2 at 2 mA cm−2, which is much higher than that of Ni3S2 nanosheet arrays (1.5 F cm−2). The corresponding asymmetric supercapacitor exhibits a wide potential window of 1.6 V and energy density up to 1.0 Wh cm−2 when the proposed array is utilized as the positive electrode with activated carbon as the negative electrode. This electrochemical performance enhancement is attributable to the hierarchical structure and synergistic cooperation of macroporous Ni foam and well-aligned Ni3S2 nanorod@nanosheet arrays. Our results represent a promising approach to the preparation of hierarchical nanorod@nanosheet arrays as high-performing electrochemical capacitors.

Ga doped Ni3S2 ultrathin nanosheet arrays supported on Ti3C2-MXene/Ni foam: An efficient and stable 3D electrocatalyst for oxygen evolution reaction

Exploring cost-efficient electrocatalysts for oxygen evolution reaction (OER) is still a huge challenge in the electrochemical energy conversion technology. In this work, Gallium (Ga)-doped Ni3S2 nanosheet arrays grown on Ti3C2-MXene/nickel foam (Ga–Ni3S2/Ti3C2/NF) have been synthesized by a successive hydrothermal and sulfidization process. The Ga doping modulates the electronic structure of Ni3S2, so tuning the adsorption energies of oxygen intermediate (∗OOH). The Ga–Ni3S2/Ti3C2/NF delivers outstanding catalytic activities toward OER with an overpotential of 340 mV at 100 mA cm−2, and exhibits superior electrochemical durability. The excellent OER performance of Ga–Ni3S2/Ti3C2/NF can be ascribed to the 3D sheet arrays morphology and optimized electronic structure. Density functional theory (DFT) calculations also demonstrate that electronic disturbance attributed to Ga doping effectively improves the activity of Ni sites, leading to stronger binding strength of ∗OOH intermediate at Ni sites nearby Ga. This study provides insights into the fabrication of advanced electrocatalysts for application.

Interfacial electronic modulation of Ni3S2 nanosheet arrays decorated with Au nanoparticles boosts overall water splitting

Rationally design and exploration of bifunctional electrocatalysts with excellent performance towards water splitting is significant for hydrogen energy economy. Herein, a novel Au/Ni3S2 heterostructure catalyst that was composed of self-supported Ni3S2 nanosheets decorated with Au nanoparticles on Ni foam was fabricated. The bifunctional catalyst exhibited excellent catalytic activities towards oxygen evolution reaction (230 mV @ 10 mA cm−2) and hydrogen evolution reaction (97 mV @ 10 mA cm−2) in 1 M KOH. The electrolytic tank using the bifunctional catalyst only required 1.52 V to deliver 10 mA cm−2 and sustained for 60 h, outperforming most of advanced bifunctional catalysts. The X-ray absorption fine structure (XAFS) and density functional theory (DFT) calculations validated that the strong electronic coupling at the interface could modulate the electronic structure of Ni3S2, thereby optimizing the free energies of the adsorbed intermediates. This work provides an atomic-scale insight into the structure-properties relation of a promising heterostructure catalyst for water splitting.

Synthesis of hierarchical Ni3S2@NiMoO4 core-shell nanosheet arrays on Ni foam for high-performance asymmetric supercapacitors

Hierarchical Ni3S2@NiMoO4 core-shell nanosheet arrays were directly fabricated on Ni foam through a simple two-step hydrothermal reaction followed by an annealing treatment. The shell, ultra-thin NiMoO4 nanosheets grew on the surface of the core, interconnected Ni3S2 nanosheet arrays. The growth density of the NiMoO4 nanosheets was adjusted by controlling the hydrothermal reaction time. When the hydrothermal time was 1 h, the as-prepared Ni3S2@NiMoO4 with a core-shell structure could achieve a high specific capacity up to 1121.4 C g−1 at a current density of 5 mA cm−2. In addition, the Ni3S2@NiMoO4 demonstrated 91.6% capacity retention of its initial value for 5000 cycles at a current density of 30 mA cm−2. Additionally, an asymmetric supercapacitor (ASC) device was assembled based on the optimized Ni3S2@NiMoO4 electrode as the positive electrode and activated carbon (AC) as the negative electrode. The ASC exhibited a maximum energy density of 28.4 W h kg−1 at a power density of 90.8 W kg−1, and showed a remarkable cycling performance with 93.1% retention of the initial capacitance after 10,000 cycles at a current density of 30 mA cm−2.

Rational design of nanorod-supported Ni3S2 nanosheet array for advanced asymmetric pseudocapacitor with a great energy density

Rational design of nanorod-supported Ni3S2 nanosheet array for advanced asymmetric pseudocapacitor with a great energy density

Efficient MOF- derived V–Ni3S2 nanosheet arrays for electrocatalytic overall water splitting in alkali

The synergistic achievement of low-cost earth-abundant electrocatalysts and high efficiency to meet renewable energy need is highly desirable yet challenging. Here, we developed a simple Ni foam self -templating route for V-doped Ni3S2 nanosheet arrays through in situ formation of metal-organic frameworks (MOFs) combined with subsequent conversion. The as-prepared MOF-V-Ni3S2/NF catalyst delivers outstanding electrocatalytic performance in the alkaline solution, which requires low overpotentials of 118.1 mV @10 mA cm−2 and 268 mV @10 mA cm−2 for hydrogen evolution reaction and oxygen evolution reaction, respectively. The V-doping and MOF-derived 3D hieratical nanostructure play a vital role in the catalytic process, which provides efficient active sites and large surface areas. Furthermore, an alkaline electrolyzer was assembled with two pieces of MOF-V-Ni3S2/NF, which achieves efficient water splitting at 1.58 V @10 mA cm−2. This strategy opens up new channels to synthesize MOF-based bifunctional electrocatalysts toward overall water spitting.

Cu-doped Ni3S2 nanosheet arrays on Ni foam as an efficient electrocatalyst for oxygen evolution reaction

Seeking efficient and inexpensive electrocatalysts for the oxygen evolution reaction (OER) is still the key to solving the electrochemical energy conversion process. In this work, Cu doped Ni3S2 nanosheet arrays grown on Ni foam have been synthesized using a two-step hydrothermal method. Doping Cu ion can effectively enhance the conductivity, accelerate charge transfer process and provide more catalytic active sites, thereby improving the OER performance of Ni3S2. In a series of Cu-doped Ni3S2 samples, Ni1.9Cu0.1-S (the chemical composition is Ni2.85Cu0.15S2) displays a small overpotential of 259 ​mV to reach a current density of 10 ​mA ​cm−2 and a Tafel slope of 54.9 ​mV dec−1, better than that of undoped Ni3S2 (with a overpotential of 274 ​mV). Also, the catalyst possesses pretty OER stability with the overpotential only rising by 1.9% after 12 ​h, which indicate the Ni1.9Cu0.1-S nanosheet arrays on Ni foam should be an effective OER catalyst in alkaline medium.

Construction of Hierarchical 2D PANI/Ni3S2 Nanosheet Arrays on Ni Foam for High‐Performance Asymmetric Supercapacitors

AbstractIn this work, a hierarchical 2D polyaniline (PANI)/Ni3S2 nanosheet arrays on Ni foam (NF) with open network was successfully developed by the growth of Ni3S2 nanosheet arrays derived from 2D Ni−MOF templates followed by the electrodeposition of a layer of PANI nanoflakes. The as‐prepared PANI/Ni3S2/NF was served as self‐standing supercapacitor electrode. The optimized PANI/Ni3S2/NF‐100 electrode exhibits a high areal capacity of 1.56 mA h cm−2 (487.5 mA h g−1) at 5 mA cm−2 and good rate capability (57.7 % retention at 50 mA cm−2), which significantly outperforms individual PANI/NF or Ni3S2/NF. Furthermore, an asymmetric supercapacitor fabricated by PANI/Ni3S2/NF‐100 and activated carbon electrodes can deliver a high energy density of 48.3 W h kg−1 at a power density of 799.8 W kg−1 with outstanding durability (85.7 % retention of the initial capacity) during 15000 consecutive charge‐discharge cycles. The superior electrochemical performance of PANI/Ni3S2/NF‐100 is attributed to the unique hierarchical PANI/Ni3S2 nanosheet arrays structure. Firstly, the hierarchical open network facilitates the electrolyte ions transport. Secondly, the ultrathin 2D Ni3S2 nanosheets lead to abundant electroactive sites for the Faradaic process, and the conductive PANI layer builds superb highway for fast electron transfer. Thirdly, the free‐standing electrode enables fast redox reaction and low interfacial resistance. Finally, the synergetic effect of Ni3S2 and PANI also contributes to the enhanced capacity.