首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
High-activity and cost-effective transition metal sulfides (TMSs) have attracted tremendous attention as promising catalysts for hydrogen evolution reaction (HER). However, a significant challenge is the simultaneous construction of abundant electrochemical active sites and the fast electronic transmission path to boost a high-efficient HER. Herein, we demonstrate a facile one-step hydrothermal preparation of MoS2 hollow nanospheres decorating Ni3S2 nanowires supported on Ni foam (NF), without any other additional template, surfactant or annealing. In this three-dimensional (3D) heterostructure, the ultrathin-layered MoS2 hollow nanospheres contribute to the promotion of the total surface area and the electrochemical active sites. Meanwhile, the Ni3S2 nanowires are beneficial to the high electrical conductivity. Consequently, the optimized MoS2/Ni3S2/NF-200-24 electrocatalyst presents an extremely superior HER activity to that of individual MoS2/NF and Ni3S2/NF. The HER overpotentials are 85 mV at 10 mA cm−2 and 189 mV at 100 mA cm−2, which are also comparable with the state-of-the-art 20% Pt/C/NF electrode at both low and high current.  相似文献   

2.
Interface engineering is considered as an effective strategy to improve the hydrogen evolution reaction (HER) performance of electrocatalysts. Herein, the Ni0.85Se/Ni3S2 heterostructure grown on nickel foam (NF) is synthesized via successive wet-chemical processes. The obtained Ni0.85Se/Ni3S2 heterostructure is firstly investigated as an HER electrocatalyst in alkaline media and exhibits more excellent electrochemical properties over Ni3S2. And it delivers a low overpotential of 145 mV at a current density of ?10 mA cm?2, and superior stability. Based on the analysis of high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectra (XPS), the enhanced HER activity is due to the modulation of surface electronic structure, ascribing from the construction of heterointerface between Ni0.85Se and Ni3S2. Meanwhile, the Ni0.85Se/Ni3S2 heterostructure prepared in this work is also verified to be employed as a promising alternative to noble metal catalysts in HER.  相似文献   

3.
In order to solve the problem of large overpotential in water electrolysis for hydrogen production, transition metal sulfides are promising bifunctional electrocatalysts for hydrogen evolution reaction/oxygen evolution reaction that can significantly reduce overpotential. In this work, Ni3S2 and amorphous MoSx nanorods directly grown on Ni foam (Ni3S2-MoSx/NF) were prepared via one-step solvothermal process, which were used as a high-efficient electrocatalyst for overall water splitting. The Ni3S2-MoSx/NF composite exhibits very low overpotentials of 65 and 312 mV to reach 10 mA cm−2 and 50 mA cm−2 in 1.0 M KOH for HER and OER, respectively. Besides, it exhibits a low Tafel slope (81 mV dec−1 for HER, 103 mV dec−1 for OER), high exchange current density (1.51 mA cm−2 for HER, 0.26 mA cm−2 for OER), and remarkable long-term cycle stability. This work provides new perspective for further the development of highly effective non-noble-metal materials in the energy field.  相似文献   

4.
Synthesizing efficient and affordable electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) remains a crucial problem on the way to practical applications for producing clean H2 fuel. Herein, high-efficiency and stable transition metal based electrocatalysts Ni0.85Se-1, Ni0.85Se-2 and Ni0.85Se-3 materials with different morphological characteristics were derived via a one-step hydrothermal route using the Ni(OH)2 and metal-organic framework (Ni-BDC and Ni-BTC) as precursors, respectively. The results showed that Ni0.85Se-2 exhibited excellent electrocatalytic activity. Subsequently, introducing carbon nanomaterials (RGO and CNTs) to form Ni0.85Se/RGO/CNTs nanocomposite material further improves the catalytic activity owing to high conductivity. The resulting Ni0.85Se/RGO/CNTs nanocomposites electrocatalyst showed a low overpotential of 232 mV and 165 mV and a low Tafel slope of 64 mV dec?1 and 98 mV dec?1 when the current density was 10 mA cm?2 for OER and HER, respectively. In addition, the Ni0.85Se/RGO/CNTs nanocomposites were used as an anode and cathode of the water electrolysis device and the overall water splitting performance was investigated. The results show just a voltage of 1.59 V was required when the current density was 10 mA cm?2 and good overall water splitting stability for 20 h. The outstanding electrocatalytic performance of Ni0.85Se/RGO/CNTs is mostly due to its noticeable porous structure, the high conductivity and the large surface area that came from RGO and CNTs.  相似文献   

5.
Technology urges to replace the state-of-the-art catalysts such as platinum with low cost, earth abundant and durable electrocatalysts for efficient hydrogen evolution (HER) reaction which is going to become the major sustainable production of energy in future. Herein, we present the heterostructure based MoS2.ZnO (MZO) heterostructures for successful electrochemical water splitting process. For HER, the prepared MoS2.ZnO nanocomposites show the over potential as low as 239 mV at cathodic current density 10 mAcm−2 with an exchange current density of 3.2 μAcm−2. A Tafel slope of about 62 mV per decade suggested to have the Volmer-Heyrovsky mechanism for the HER process with MoS2.ZnO nanocomposite as the catalyst. The small Tafel slope indicates a promising electrocatalyst for HER in practical application. The strong interface formation at the MoS2.ZnO heterostructure facilitates higher catalytic activity and excellent cycling stability. The heterostructure formation based on semiconductor two dimensional (2D) transition metal dichalcogenides (TMDC) open up new avenues for effective manipulation of HER catalysts.  相似文献   

6.
The development of highly active and low-cost catalysts for hydrogen evolution reaction (HER) is significant for the development of clean and renewable energy research. Owing to the low H adsorption free energy, molybdenum disulfide (MoS2) is regarded as a promising candidate for HER, but it shows low activity for oxygen evolution reaction (OER). Herein, graphene-supported cobalt-doped ultrathin molybdenum disulfide (Co–MoS2/rGO) was synthesized via a one-pot hydrothermal method. The obtained hybrids modified electrode exhibits a high HER catalytic activity with a low overpotential of 147 mV at the current density of 10 mA cm−2, a small Tafel slope of 49.5 mV dec−1, as well as good electrochemical stability in acidic electrolyte. Meanwhile, the catalyst shows remarkable OER activity with a low overpotential of 347 mV at 10 mA cm−2. The superior activity is ascribed not only to the high conductivity originated from the reduced graphene, but also to the synergistic effect between MoS2 and cobalt.  相似文献   

7.
Developing earth-abundant and highly active bifunctional electrocatalysts are critical to advance sustainable hydrogen production via alkaline water electrolysis but still challenging. Herein, heterojunction hybrid of ultrathin molybdenum disulfide (MoS2) nanosheets and non-stoichiometric nickel sulfide (Ni0.96S) is in situ prepared via a facile one-step hydrothermal strategy, followed by annealing at 400 °C for 1 h. Microstructural analysis shows that the hybrid is composed of intimate heterojunction interfaces between Ni0.96S and MoS2 with exposed active edges provided by ultrathin MoS2 nanosheets and rich defects provided by non-stoichiometric Ni0.96S nanocrystals. As expected, it is evaluated as bifunctional electrocatalysts to produce both hydrogen and oxygen via water electrolysis with a hydrogen evolution reaction (HER) overpotential of 104 mV at 10 mA cm−2 and an oxygen evolution reaction (OER) overpotential of 266 mV at 20 mA cm−2 under alkaline conditions, outperforming most current noble-metal-free electrocatalysts. This work provides a simple strategy toward the rational design of novel heterojunction electrocatalysts which would be a promising candidate for electrochemical overall water splitting.  相似文献   

8.
The development of inexpensive and competent electrocatalysts for high-efficiency hydrogen evolution reaction (HER) has been greatly significant to realize hydrogen production in large scale. In this paper, we selected the inexpensive and commercially accessible stainless steel as the conductive substrate for loading MoS2 as a cathode for efficient HER under alkaline condition. Interconnected MoS2 nanosheets were grown uniformly on 316-type stainless steel meshes with different mesh numbers via a facile hydrothermal way. And the optimized MoS2/stainless steel electrocatalysts exhibited superior electrocatalytic performance for HER with a low overpotential of 160 mV at 10 mA cm−2 and a small Tafel slope of 61 mV dec−1 in 1 M KOH. Systematic study of the electrochemical properties was performed on the MoS2/stainless steel electrocatalysts in comparison with the commonly used carbon cloth to better comprehend the origin of the superior HER performance as well as stability. By collaborative optimization of MoS2 nanosheets and the cheap stainless steel substrate, the interconnected MoS2 nanosheets on stainless steel provide an alternative strategy for the development of efficient and robust HER catalysts in strong alkaline environment.  相似文献   

9.
Fabricating earth-abundant bifunctional water splitting electrocatalysts with high efficiencies to replace noble metal-based Pt and IrO2 catalysts is in great demand for the development of clean energy conversion technologies. Molybdenum disulfide (MoS2) nanostructures have attracted much attention as promising material for hydrogen evolution reaction (HER). The production of hydrogen gas by help of potential efficient earth abundant metal oxides, and stable electrolysis seems a promising for hydrogen evolution reaction pathway in 1 M potassium hydroxide electrolyte media is a hot research topic in the field for clean energy conversion, renewable energies and storage. Here we propose asystem composed NiO nanostructures and MoS2 deposited on (MoS2@NiO). Here, by hydrothermal method NiO prepared and MoS2@NiO by an electrospinning technique complex, can be used as catalyst to produce a large amount of hydrogen gas bubbles. The NiO nanostructures composite having highest synergistic behavior fully and covered by the MoS2. For the MoS2@NiO nano composite catalyst, experiment applied in 1 M KOH for the production of hydrogen evolution reaction which exhibits distinct properties from the bulk material. Overpotential values recorded low 406 mV and current density 10 mA cm−2 measured. Co-catalysts characterized by using different techniques for deep study as scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Owing to their unique structure, as-prepared nanocomposite exhibited enhanced catalytic performance for HER due to high electroactive surface area and swift electron transfer kinetics. Based on the HER polarization curves at low potential electrochemical to examine the effects of intercalants HER catalytic efficiency. Our findings establish low Tafel slope (44 mV/decade) and the catalyst stable for at least 13 h. This simple exploitation of MoS2@NiO composite catalysts depending on the intended application of their electrochemistry.  相似文献   

10.
Seeking the efficient and robust electrocatalysts necessarily enhances performance of hydrogen evolution reaction (HER). Increasing the surface active sites is a means to improve the performance. Herein, we use the Ni0·85Se anchored on reduction of graphene oxide (Ni0·85Se/rGO) hybrid material skillfully established by one-step facile hydrothermal method as a robust and stable electrocatalyst applying to hydrogen evolution reaction (HER). In terms of morphology, Ni0·85Se nanospheres composed of many nanosheets are uniformly distributed on the graphene sheet layer. We also detailedly analyze its properties. Based on the interaction between Ni0·85Se and rGO, and the roles of graphene are as a substrate to heighten conductivity, possesses more active surface area by limiting growth of Ni0·85Se, and increases dispersion for exposing more active surface area and enlarge ion/electron transfer rate. In HER, the Ni0·85Se/rGO catalyst displays the overpotential of 128 mV with a common current density of 10 mA cm−2, a small Tafel slope of 91 mV dec−1, an extremely low onset potential of 37 mV, outstanding stability that a high current retention of 97.7% after 1000 cycles and well long-term stability for 18 h, outperforming the capability of Ni0·85Se nanospheres in alkaline solution for HER. The above results indicate that the Ni0·85Se/rGO hybrid material is a good HER ability and non-noble metal electrocatalyst has potential value in HER.  相似文献   

11.
In targeting the most important energy and environmental issues in current society, the development of low-cost, bifunctional electrocatalysts for urea-assisted electrocatalytic hydrogen (H2) production is an urgent and challenging task. In this work, interlaced rosette-like MoS2/Ni3S2/NiFe-layered double hydroxide/nickel foam (LDH/NF) is successfully synthesized by a two-step hydrothermal reaction. Due to its unique interlaced heterostructure, MoS2/Ni3S2/NiFe-LDH/NF exhibits excellent bifunctional catalytic activity towards the urea oxidation reaction (UOR) and the hydrogen evolution reaction (HER) in 1.0 M KOH with 0.5 M urea. In a concurrent two-electrode electrolyser (MoS2/Ni3S2/NiFe-LDH/NF(+,-)), only voltage of 1.343 V is required to reach 50 mA cm−2, which is 216 mV lower than for pure water splitting. Furthermore, after 16 h of urea electrolysis in 1.0 M KOH with 0.5 M urea, the current density remains at 98% of the original value. Thus, the catalyst is not only favorable for H2 production, but also has great significance for the problem of urea-rich wastewater treatment.  相似文献   

12.
Searching for efficient, stable and low-cost nonprecious catalysts for oxygen and hydrogen evolution reactions (OER and HER) is highly desired in overall water splitting (OWS). Herein, presented is a nickel foam (NF)-supported MoS2/NiFeS2 heterostructure, as an efficient electrocatalyst for OER, HER and OWS. The MoS2/NiFeS2/NF catalyst achieves a 500 mA cm−2 current density at a small overpotential of 303 mV for OER, and 228 mV for HER. Assembled as an electrolyzer for OWS, such a MoS2/NiFeS2/NF heterostructure catalyst shows a quite low cell voltage (≈1.79 V) at 500 mA cm−2, which is among the best values of current non-noble metal electrocatalysts. Even at the extremely large current density of 1000 mA cm−2, the MoS2/NiFeS2/NF catalyst presents low overpotentials of 314 and 253 mV for OER and HER, respectively. Furthermore, MoS2/NiFeS2/NF shows a ceaseless durability over 25 h with almost no change in the cell voltage. The superior catalytic activity and stability at large current densities (>500 mA cm−2) far exceed the benchmark RuO2 and Pt/C catalysts. This work sheds a new light on the development of highly active and stable nonprecious electrocatalysts for industrial water electrolysis.  相似文献   

13.
In recent years, the exploration of efficient and stable noble-metal-free electrocatalysts is becoming increasingly important, used mainly for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). In this work, a new ultrathin porous Cu1-xNixS/NF nanosheets array was constructed on the 3D nickel skeleton by two-step method: hydrothermal method and vulcanization method. Through these two processes, Cu1-xNixS/NF has a larger specific surface area than that of foamed nickel (NF) and Cu1-xNixO/NF. The Cu1-xNixS/NF materials show excellent catalytic activity by accelerating the electron transfer rate and increase the amount of H2 and O2 produced. The lower overpotential was obtained only 350 mV at 20 mA cm−2 for OER, not only that, but also the same phenomenon is pointed out in HER, optimal Cu1-xNixS/NF presents low overpotentials of 189 mV to reach a current density of 10 mA cm−2 in 1.0 M KOH for HER. Both OER and HER shows a lower Tafel slope: 51.2 mV dec−1 and 127.2 mV dec−1, subsequently, the overall water splitting activity of Cu1-xNixS/NF was investigated, and the low cell voltage was 1.64 V (current density 10 mA cm−2). It can be stable for 14 h during the overall water splitting reaction. These results fully demonstrate that Cu1-xNixS/NF non-precious metal materials can be invoked become one of the effective catalysts for overall water splitting, providing a richer resource for energy storage.  相似文献   

14.
We present a facile methodology for the synthesis of a novel 2D-MoS2, graphene and CuNi2S4 (MoS2-g-CuNi2S4) nanocomposite that displays highly efficient electrocatalytic activity towards the production of hydrogen. The intrinsic hydrogen evolution reaction (HER) activity of MoS2 nanosheets was significantly enhanced by increasing the affinity of the active edge sites towards H+ adsorption using transition metal (Cu and Ni2) dopants, whilst also increasing the edge sites exposure by anchoring them to a graphene framework. Detailed XPS analysis reveals a higher percentage of surface exposed S at 17.04%, of which 48.83% is metal bonded S (sulfide). The resultant MoS2-g-CuNi2S4 nanocomposites are immobilized upon screen-printed electrodes (SPEs) and exhibit a HER onset potential and Tafel slope value of – 0.05 V (vs. RHE) and 29.3 mV dec−1, respectively. These values are close to that of the polycrystalline Pt electrode (near zero potential (vs. RHE) and 21.0 mV dec−1, respectively) and enhanced over a bare/unmodified SPE (– 0.43 V (vs. RHE) and 149.1 mV dec−1, respectively). Given the efficient, HER activity displayed by the novel MoS2-g-CuNi2S4/SPE electrochemical platform and the comparatively low associated cost of production for this nanocomposite, it has potential to be a cost-effective alternative to Pt within electrolyser technologies.  相似文献   

15.
Self-standing and hybrid MoS2/Ni3S2 foam is fabricated as electrocatalyst for hydrogen evolution reaction (HER) in alkaline medium. The Ni3S2 foam with a unique surface morphology results from the sulfurization of Ni foam showing a truncated-hexagonal stacked sheets morphology. A simple dip coating of MoS2 on the sulfurized Ni foam results in the formation of self-standing and hybrid electrocatalyst. The electrocatalytic HER performance was evaluated using the standard three-electrode setup in the de-aerated 1 M KOH solution. The electrocatalyst shows an overpotential of 190 mV at ?10 mA/cm2 with a Tafel slope of 65.6 mV/dec. An increased surface roughness originated from the unique morphology enhances the HER performance of the electrocatalyst. A density functional approach shows that, the hybrid MoS2/Ni3S2 heterostructure synergistically favors the hydrogen adsorption-desorption steps. The hybrid electrocatalyst shows an excellent stability under the HER condition for 12 h without any performance degradation.  相似文献   

16.
Electrochemical hydrogen evolution reaction (HER) via the splitting of water has required electrocatalysts with cost-effectiveness, environmentally friendliness, high catalytic activity, and superior stability to meet the hydrogen economy in future. In this context, we report the successful synthesis of self-standing mesoporous Ni2P–MoP2 nanorod arrays on nickel foam (Ni2P–MoP2 NRs/3D-NF) through an effective phosphidization of the corresponding NiMoO4 NRs/3D-NF. The as-synthesis Ni2P–MoP2 NRs/3D-NF, as an efficient HER electrocatalyst, exhibits small overpotential of 82.2 and 124.7 mV to reach current density of 10 and 50 mA cm−2, a low Tafel slope of 52.9 mV dec−1 and it retains its catalytic performance for at least 20 h in alkaline condition. Our work also offers a new strategy in designing and using transition metal phosphide-based 3D nanoarrays catalysts with enhanced catalytic efficiency for mass production of hydrogen fuels.  相似文献   

17.
Integrating MoS2 with carbon-based materials, especially graphene, is an effective strategy for preparing highly active non-noble-metal electrocatalysts in the hydrogen evolution reaction (HER). This work demonstrates a convenient hydrothermal method to fabricate molybdenum disulfide nanosheets/nitrogen-doped reduced graphene oxide (MoS2/NGO) hybrids using polyoxomolybdate as the Mo precursor. Introducing more defects and expanding interlayer spacing of MoS2 can be achieved through decreasing the pH value of the reactive system due to the existed high-nuclear polyoxometalate clusters. MoS2/NGO hybrids prepared at low pH exhibit superior HER activity to those obtained at high pH. MoS2/NGO-pH1.5 exhibits an ultralow overpotential of 81 mV at 10 mA cm−2, a low Tafel slope of 60 mV·dec−1 and good stability in alkaline electrolyte. Such excellent electrocatalytic activity is contributed by the abundant HER catalytic active sites, the increased electrochemically-accessible area and the synergetic effects between the active MoS2 catalyst and NGO support.  相似文献   

18.
The electrochemical production of hydrogen is a promising and flexible approach towards the conversion of intermittent renewable energy sources into clean chemical fuel. However, low-cost, efficient, and durable electrocatalysts are yet to be developed to attain economies of scale in hydrogen generation. In this study, we fabricated highly ordered free-standing TiO2 nanotube arrays (TiO2-NTs), by simply anodizing Ti foils. The tube length, diameter, wall thickness, and surface structure of the TiO2-NTs can be controlled by adjusting the anodization conditions. Subsequently, we synthesized and supported MoS2 layers on free-standing TiO2-NTs as an active material for the hydrogen evolution reaction (HER), using a slow evaporation method. The layers of MoS2 uniformly disperse on the entire surface of the TiO2-NTs composite. The electrochemical test shows that the MoS2-supported free-standing (MoS2/TiO2-NTs) system exhibits excellent HER performance in acidic media with a low overpotential at 10 mA cm−2 (170 mV), as well as small Tafel slope (70 mV decade−1). Also, the MoS2/TiO2-NTs displays superior durability for HER after 5000 continuous potential cycles between −0.4 and + 0.2 (V vs. RHE). Our results demonstrate the potential application of MoS2/TiO2-NTs composite for cost-effective electrochemical production of hydrogen.  相似文献   

19.
The MoS2/Ti3C2 catalyst with a unique sphere/sheet structure were prepared by hydrothermal method. The MoS2/Ti3C2 heterostructure loading 30% Ti3C2 has a maximum hydrogen production rate of 6144.7  μmol g−1 h−1, which are 2.3 times higher than those of the pure MoS2. The heterostructure maintains a high catalytic activity within 4 cycles. The heterostructure not only effectively reduce the recombination of photogenerated electrons and holes, but also provide more activation sites, which promotes the photocatalytic hydrogen evolution reaction (HER). These works can provide reference for the development of efficient catalysts in photocatalytic hydrogen evolution.  相似文献   

20.
Developing efficient and cost-effective transition metal-based electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial to generate clean and renewable hydrogen energy. The construction of hybrid catalysts with multiple active sites is an effective approach to promote catalytic performance. Herein, a molybdenum disulfide (MoS2)-based hybrid with N-doped carbon wrapped CoFe alloy (MoS2/CoFe@NC) was synthesized through a typical hydrothermal method. The MoS2/CoFe@NC exhibits excellent electrocatalytic performance with overpotentials of 172 mV for HER and 337 mV for OER at 10 mA cm−2, and long-term stability of 24-h electrolytic reaction in 1 M KOH solution. The chemical coupling between MoS2 and CoFe@NC provides improved electronic structures and more accessible active sites. The CoFe@NC substrate accelerates the charge transfer to MoS2 through a synergistic effect. This work demonstrates that the CoFe@NC is a promising substrate for depositing MoS2 nanosheets (NSs) to achieve excellent catalytic performance for both HER and OER.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号