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1.
Herein we report a heterostructure with ultrathin nanosheets of Co-doped molybdenum sulfide on CdS nanorod array (donated as CdS@CoMo2S4/MoS2) by hydrothermal synthesis. Firstly, elemental Co doping MoS2 (CoMo2S4) delivers the double benefits of increased active sites and enhanced conductivity. Secondly, the structural characteristics maximally exposes the MoS2 edges and enlarges interfacial contact area between the composite catalyst and electrolyte, as well as the efficient interfacial charge transfer. The ratio of CoMo2S4/MoS2 in CdS@CoMo2S4/MoS2 plays a crucial role for the enhanced photo-assistant electrocatalytic hydrogen evolution reaction (HER). We can tune the ratio of CoMo2S4/MoS2 by controlling the preparation time or the ratio of precursor of Co/Mo. The catalyst with predominant MoS2 phase shows superior photocatalytic HER performance with a high H2 production rate of 46.60 μmol mg−1 h−1. Meanwhile, the catalyst with predominant CoMo2S4 phase exhibits not only relatively low overpotential of 172 mV at 10 mA cm−2, which outperforms most values that have been reported on catalyst supported on ITO substrate, but also possesses H2 production rate of 23.47 μmol mg−1 h−1. The superior photo-assistant electrocatalytic HER activity results from the synergistically structural and electronic modulations, as well as the proper energy band alignment between MoS2 and CdS. This investigation could provide an approach to integrate the electro- and photocatalytic activities for HER, especially the photo responding behaviour at a bias potential which is meaningful to produce H2 for actual application.  相似文献   

2.
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   

3.
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   

4.
Molybdenum disulfide (MoS2), attracts great attention in hydrogen evolution reaction (HER) field, however, low catalytic activity sites and poor conductivity still limit its further application. In this study, an efficient hydrogen evolution electrode with nano-pom-pom multiphasic MoS2 uniformly grew on porous carbonized wood (NP MoS2/CW) was developed. Interestingly, the nano-pom-pom are stacked from sheets of MoS2. Fully exposed active edges of nano-pom-pom MoS2 and high excellent electrical conductivity of carbonized wood enhance collectively electrocatalytic performance for HER. Specifically, the NP MoS2/CW electrode requires an overpotential of 109.5 mV and 305 mV to achieve the current density of 10 mA cm−2 and 400 mA cm−2, respectively (0.5 M H2SO4). NP MoS2/CW has excellent electrocatalytic performance and stability in acidic and alkaline media due to the perfect combination of NP MoS2 unique nanostructure and the unique properties of CW. Therefore, the present work provides a promising strategy into the rational development and utilization of MoS2 for the development of hydrogen evolution.  相似文献   

5.
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   

6.
The design of p-n heterojunction photocatalysts to overcome the drawbacks of low photocatalytic activity that results from the recombination of charge carriers and narrow photo-response range is promising technique for future energy. Here, we demonstrate the facile hydrothermal synthesis for the preparation of Bi2O3/MoS2 p-n heterojunction photocatalysts with tunable loading amount of Bi2O3 (0–15 wt%). The structure, surface morphology, composition and optical properties of heterostructures were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV–visible absorption spectroscopy, Brunauer-Emmett-Teller (BET) surface area, photoluminescence (PL), electrochemical impedance spectroscopy (EIS). Compare to pure Bi2O3 and MoS2, the Bi2O3/MoS2 heterostructures displayed significantly superior performance for photocatalytic hydrogen (H2) production using visible photo-irradiation. The maximum performance for hydrogen evolution was achieved over Bi2O3/MoS2 photocatalyst (10 μmol h−1g−1) with Bi2O3 content of 11 wt%, which was approximately ten times higher than pure Bi2O3 (1.1 μmol h−1g−1) and MoS2 (1.2 μmol h−1g−1) photocatalyst. The superior performance was attributed to the robust light harvesting ability, enhanced charge carrier separation via gradual charge transferred pathway. Moreover, the increased efficiency of Bi2O3/MoS2 heterostructure photocatalyst is discussed through proposed mechanism based on observed performance, band gap and band position calculations, PL and EIS data.  相似文献   

7.
The development of highly efficient binary heterostructures with enhanced electrocatalytic activities is vital for reducing the energy consumed by the hydrogen evolution reaction (HER). Herein, we successfully design and synthesize an eco-friendly Ag3PO4/1T-2H MoS2 heterostructure to catalyze the HER process. Micromorphology and microstructure studies show that the Ag3PO4 nanoclusters are well dispersed with abundant catalytically active sites on the surface of the 1T-2H MoS2 nanoflowers. X-ray photoelectron spectroscopy confirms the stable oxidation state and electronic interactions in the 2 wt% Ag3PO4/1T-2H MoS2 nanostructure. Benefitting from the strong electronic interactions and advantages of abundant heterogeneous interfaces and catalytically active sites, the 2 wt% Ag3PO4/1T-2H MoS2 heterostructure delivers excellent and durable electrochemical HER activity in alkaline solution, with a low overpotential of 149 mV for the HER at 10 mA cm−2, in clear improvement over 1T-2H MoS2. The enhanced electrocatalytic activity is ascribed to the abundant catalytically active sites, rapid charge transport, and Ag3PO4/1T-2H MoS2 synergism. This study provides a novel strategy for exploring and synthesizing low-cost binary electrocatalysts that enhance the electrochemical HER performance in energy-conversion applications.  相似文献   

8.
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   

9.
There are great challenges to develop and fabricate a high performance, low-cost and stable non-platinum catalyst for hydrogen evolution reaction (HER). In our study, we firstly developed a simple method to successfully fabricate a new MoS2/NiCo2S4 heterostructure by a two-step hydrothermal method, and studied the HER property of MoS2/NiCo2S4, where the as-prepared NiCo-layered double hydroxide (NiCo-LDH) was used as the precursor of NiCo2S4. Benefitting from the prominent synergistic effect between NiCo2S4 and MoS2, MoS2 provided massive catalytic active edge sites, and NiCo2S4 enhanced the conductivity of the composite. As a result, the MoS2/NiCo2S4 showed excellent HER catalytic activity, with a current of 10 mA cm−2 at overpotential of 94 mV for HER and a low Tafel slope of 46 mV dec−1, and good cycling stability in Alkaline Media. As well as, our work offered one promising high active and stable non-platinum catalyst for overall water splitting.  相似文献   

10.
An oxygen-vacancy rich, bismuth oxide (Bi2O3) based MoS2/Bi2O3 Z-scheme heterojunction catalyst (2-BO-MS) was prepared in an autoclave hydrothermal method using ethanol and water. The performance of MoS2/Bi2O3 catalyst was examined for photocatalytic hydrogen evolution, photoelectrochemical activity, and crystal violet (CV) dye degradation by comparing with pristine Bi2O3 and MoS2. The hydrogen evolution performances of 2-BO-MS catalyst exhibited 3075.21 μmol g−1 h−1, which is 7.18 times higher than that of MoS2 (428.14 μmol g−1 h−1). The XPS, XRD and HRTEM analyses covered that the superior photocatalytic performance of 2-BO-MS catalyst might have stemmed out due to the existence of oxygen vacancies, enhanced strong interfacial interaction between MoS2 and Bi2O3 and specific surface area. The in-depth investigation has been performed for MoS2/Bi2O3 Z-scheme heterojunction using several characterization techniques. Moreover, the photocatalytic mechanism for hydrogen evolution and photodegradation were proposed based on trapping experiment results. This results acquired using MoS2/Bi2O3 Z-scheme heterojunction would be stepping stone for developing heterojunction catalyst towards attaining outstanding photocatalytic activity.  相似文献   

11.
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   

12.
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   

13.
MoS2 is a promising noble-metal-free electrocatalyst for the hydrogen evolution reaction. Extensive trials have been carried out to increase its low electrical conductivity and insufficient active sites. Here, a remarkable electrocatalyst for hydrogen evolution is developed based on the in-situ preparation of MoS2 confined in graphene nanosheets. Graphene effectively controls the growth of MoS2 and immensely increases the conductivity and structural stability of the composite materials. Remarkably, because of the plentiful active sites, sufficient electrical contact and transport, MoS2 particles confined in graphene nanosheets exhibit an onset overpotential as small as 32 mV, an overpotential approaching 132 mV at 10 mA cm−2, and a low Tafel slope of 45 mV dec−1. This work presents a reasonable architecture for practical applications in efficient electrocatalytic H2 generation.  相似文献   

14.
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   

15.
The study of high efficiency and low cost catalysts is of great significance to the overall development of electrochemistry. In this paper, NiCoM (M = P, S, Se, O)–Ni3S2–MoS2 hybrid material was prepared by hydrothermal, calcination and hydrothermal three-step reaction method, and its hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline environment were studied and compared. The experimental results showed that at 10 mA cm?2, the overpotential of NiCoP–Ni3S2–MoS2 was only 140 mV for HER, while the overpotential of NiCoSe–Ni3S2–MoS2 was only 160 mV for OER. Compared with other catalysts, the activity of NiCoP–Ni3S2–MoS2 and NiCoSe–Ni3S2–MoS2 was higher, and the chemical reagents needed for preparation were cheap and low cost. What is noteworthy is that the morphology of NiCoP–Ni3S2–MoS2 material change after long time stability test for hydrogen evolution reaction, the change makes the performance of the samples toward a better direction. A series of characterization found that the surface of the NiCoP–Ni3S2–MoS2 samples increased more holes and more active site, and did not produce new material after other characterization. Density functional theory calculation shows that the presence of this MoS2 material accelerates the kinetics of hydrogen production and this Co2P material enhances the conductivity of the material. Their synergistic effect makes the NiCoP–Ni3S2–MoS2 catalyst exhibit enhanced hydrogen production activity. The bramble structure of NiCoSe–Ni3S2–MoS2 allows the sample to have more active sites and higher electrocatalytic activity during the OER process. This experiment provides new insights into the preparation of robust water splitting catalysts by simple methods.  相似文献   

16.
In the present work, the effect of transition metals (Ni, Fe, Co) doping on 2-dimensional (2D) molybdenum disulfide (MoS2) nanosheets for electrocatalytic hydrogen evolution reaction (HER) was explored. A simple and cost-effective hydrothermal method was adopted to synthesis transition metals doped MoS2 nanosheets. The morphological and spectroscopic studies evidence the formation of high-quality MoS2 nanosheets with the randomly doped metal ions. Notably, the Ni–MoS2 displayed superior HER performance with an overpotential of ?0.302 V vs. reversible hydrogen electrode (RHE) (to attain the current density of 10 mA cm?2) as compared to the other transition metals doped MoS2 (Co–MoS2, Fe–MoS2). From the Nyquist plot, superior charge transport from the electrocatalyst to the electrolyte in Ni–MoS2 was realized and confirmed that Ni doping provides the necessary catalytic active sites for rapid hydrogen production. The stable performance was confirmed with the cyclic test and chronoamperometry measurement and envisaged that hydrothermally synthesized Ni–MoS2 is a highly desirable cost-effective approach for electrocatalytic hydrogen generation.  相似文献   

17.
Molybdenum disulfide (MoS2) is considered a low-cost material that may replace platinum-based electrocatalysts towards hydrogen evolution reaction (HER). However, the catalytic activity of MoS2 is limited by the low conductivity and lack of active sites. Here, a biomass carbon dots-molybdenum disulfide (BCDs-MoS2) composite was synthesized as a HER catalyst by a simple hydrothermal method. The BCDs-MoS2 catalyst displayed excellent electrocatalytic performance for HER with lower onset overpotential (115 mV), smaller Tafel slope (56.57 mV dec?1) as well as high cycling stability, which superior to those of homemade MoS2, commercial MoS2, and most of the reported MoS2-based catalysts. According to the characterization results of morphology, surface properties, and valence states of elements, the outstanding catalytic activity of BCDs-MoS2 is ascribed to its loose structure with a large specific surface area along with abundant edges and defects, and the increase in the amount of S22? and S2? which possess higher activity due to the addition of the BCDs. This study can afford a new strategy to design high performance HER catalysts.  相似文献   

18.
Water splitting is an appealing way of producing hydrogen fuel, which requires efficient and affordable electrode materials to make the overall process viable. In the last couple years, abundant transition metals (and their compounds and hybrids) attracted ever-growing attention as the alternatives of noble metals. Particularly the layered transition metal dichalcogenide (TMDs) are interesting with their stability and promising electrocatalytic performance for hydrogen evolution reaction (HER). However, the neat TMDs are often poor in terms of the abundance of catalytically active sites and electrical conductivity, which limit their application potential significantly. Herein, as a proof-of-concept, we report on the design of a high-performance electrocatalyst system formed by the decoration of ultrasmall molybdenum sulfide (MoS2) nanosheets on carbon nanotubes (CNTs). The ultrasmall MoS2 nanosheets provide distorted lattice, confined size and rich defects, which endows the resulting electrocatalysts (MoS2/CNT) with abundant active sites. The CNTs, on the other hand, serve as the conductive net for ensuring electrocatalytic performance. As a result, the hybrid electrocatalyst exhibits excellent electrocatalytic performance for HER, achieving a large current density of 100 mA cm−2 at overpotential of only 281 mV and a small Tafel slope of 43.6 mV dec−1 along with a decent stability. Our results are of high interest for electrocatalyst technologists as well as hydrogen fuel researchers.  相似文献   

19.
Exploring inexpensive and earth-abundant electrocatalysts for hydrogen evolution reactions is crucial in electrochemical sustainable chemistry field. In this work, a high-efficiency and inexpensive non-noble metal catalysts as alternatives to hydrogen evolution reaction (HER) was designed by one-step hydrothermal and two-step electrodeposition method. The as-prepared catalyst is composed of the synergistic MoS2–Co3S4 layer decorated by ZnCo layered double hydroxides (ZnCo-LDH), which forms a multi-layer heterostructure (ZnCo/MoS2–Co3S4/NF). The synthesized ZnCo/MoS2–Co3S4/NF exhibits a small overpotential of 31 mV and a low Tafel plot of 53.13 mV dec?1 at a current density of 10 mA cm?2, which is close to the HER performance of the overpotential (26 mV) of Pt/C/NF. The synthesized ZnCo/MoS2–Co3S4/NF also has good stability in alkaline solution. The excellent electrochemical performance of ZnCo/MoS2–Co3S4/NF electrode originates from its abundant active sites and good electronic conductivity brought by the multilayer heterostructure. This work provides a simple and feasible way to design alkaline HER electrocatalysts by growing heterostructures on macroscopic substrates.  相似文献   

20.
The development of cheap, efficient, and active non-noble metal electrocatalysts for total hydrolysis of water (oxygen evolution reaction (OER) and hydrogen evolution reaction (HER)) is of great significance to promote the application of water splitting. Herein, a heterogeneous structured electrode based on FeAlCrMoV high-entropy alloy (HEA) was synthesized as a cost-effective electrocatalyst for hydrogen and oxygen evolution reactions in alkaline media. In combination of the interfacial synergistic effect and the high-entropy coordination environment, flower-like HEA/MoS2/MoP exhibited the excellent HER and OER electrocatalytic performance. It showed a low overpotential of 230 mV at the current density of 10 mA cm−2 for OER and 148 mV for HER in alkaline electrolyte, respectively. Furthermore, HEA/MoS2/MoP as both anode and cathode also exhibited an overpotential of 1.60 V for overall water splitting. This work provides a new strategy for heterogeneous structure construction and overall water splitting based on high-entropy alloys.  相似文献   

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