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1.
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   

2.
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   

3.
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   

4.
The metal-free carbonaceous catalysts are one of the promising candidates for efficient electrocatalytic hydrogen production. Aiming at demonstrating the high electrocatalytic activity of the hydrogen evolution reaction (HER), we synthesized the biomass rice husk-derived corrugated graphene (RH-CG) nanosheets via the KOH activation. The 700 °C-activated RH-CG nanosheets exhibited the large specific surface area as well as the high electrical conductivity. When using the RH-CG nanosheets as a HER electrocatalyst in 0.5 M H2SO4, the excellent HER activities with a small overpotential (9 mV at 10 mA/cm2) and a small Tafel slope (31 mV/dec) were achieved. The results provide a new strategy for materializing the superb biomass-derived electrocatalyst for highly efficient hydrogen production.  相似文献   

5.
Increasing efforts have been devoted to enhancing the cathode activity towards oxygen reduction and improve power generation of air breathing microbial fuel cells. Exploring non-precious metal and highly active cathodic catalyst plays a key role in improving cathode performance. Our work aims to investigate the electrocatalyst behavior and power output of the single-chamber MFC equipped with carbon nanotubes hybridized molybdenum disulfide nanocomposites (CNT/MoS2) cathode. MoS2 nanosheets embedded into the CNTs network structure is synthesized by a facile hydrothermal method. The CNT/MoS2-MFC achieves a maximum power density of 53.0 mW m−2, which is much higher than those MFCs with pure CNTs (21.4 mW m−2) or solely MoS2 (14.4 mW m−2) cathode. The oxygen reduction reaction (ORR) test also demonstrates a promoted electrocatalytic activity of synthesized material, which may be attributed to the special interlaced structure and abundant oxygen chemisorption sites of CNT/MoS2. Such CNTs-based noble-metal-free catalyst presents a new approach to the application of MFCs cathode materials.  相似文献   

6.
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   

7.
Structural engineering of highly efficient electrocatalysts based on 2D transition metal dichalcogenides (TMDs) for hydrogen evolution reaction (HER) is of great significance for sustainable energy conversion processes. Herein, a novel basal-plane engineering of 2D colloidal VSe2 nanosheets has been developed for highly enhanced HER performance via a synergistic combination of atmosphere plasma (AP) treatment and Co basal-plane doping. Systematic experiments and theoretical calculations show that the AP treatment not only efficiently removes the organic ligands, but also introduces defects and cracks as more active sites on the basal plane; while the Co basal-plane doping and defects further optimize Gibbs free energy of hydrogen adsorbed on the Se sites. Such AP treated 5 % Co doped VSe2 electrocatalyst exhibits onset overpotential of only 160 mV, Tafel slope of 42 mV/decade and turnover frequency (TOF) of 6.4 S−1 at 260 mV, comparable to the most active TMDs electrocatalysts. This work provides fresh insights into the utilization of “clean surface”, defects/cracks and heteroatom doping on basal plane of 2D nanosheets for catalytic application.  相似文献   

8.
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   

9.
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   

10.
Production of hydrogen from electrochemical water splitting has been regarded as one of the most economic and sustainable techniques for green fuel production. It is significant and challengeable to develop highly efficient and low cost noble metal-free electrocatalysts. Presently, molybdenum-based electrocatalysts were regarded as potential alternatives for the hydrogen evolution reaction (HER). Here, the well-dispersed and ultrasmall Mo2C nanoparticles (NPs) anchored on 2D carbon nanosheets were synthesized by designing chelate precursor and following pyrolysis, which was proved to be an effective approach for preparing carbon-loaded Mo2C NPs. The as-obtained Mo2C/C material exhibits an outstanding activity and stability in hydrogen evolution reaction (HER). It needs an overpotential of 147 mV to drive 10 mA cm−2 and Tafel slope is 64.2 mV dec−1 in alkaline medium, implying that Mo2C/C material will be a potential noble metal-free electrocatalyst for HER. The design of Mo-chelate precursor is a feasible route to synthesize ultrafine Mo2C and it can provide a reference for synthesizing other nanoparticles and hindering particle coalescence at high preparation temperature.  相似文献   

11.
The layered MoS2 nanostructures have been widely used in the electrochemical hydrogen evolution reaction (HER), but rarely applied in overall water splitting application for their ignorable oxygen evolution reaction (OER) activity. To address this issue, a novel self-standing and bifunctional electrocatalyst, consisting of Co-doped MoS2 nanosheets anchored on carbon fiber paper, has been prepared via hydrothermal method. Taking advantage of conductive substrate of carbon fiber paper, sufficient-exposed active edges of MoS2 sheets, and metallic character caused by Co-doping, our electrode exhibits high-efficient bifunctional activities for the overall water splitting in alkaline electrolyte (1 M KOH), which can produce a current density of 20 mA cm−2 at an overpotential of 197 mV for HER and 235 mV for OER.  相似文献   

12.
Molybdenum sulfide (MoS2) as a graphene-like sheet material has attracted wide attention owing to the potential for hydrogen evolution reaction (HER). However, the large-scale application of MoS2 is still difficult due to the inherent poor conductivity and insufficient active edge sites. Herein, we develop a simple method to grow P-doped MoS2 nanosheets on carbon cloth for high efficiency HER. The 2D carbon cloth can prevent the stacking of MoS2 nanosheets and improve the conductivity with the doping of P atoms. As a result, the P–MoS2/CC-300 shows the excellent electrocatalytic activity with an overpotential of 81 mV at 10 mA cm?2 and the lower Tafel slope of 98 mV/dec. Furthermore, it also shows the good electrocatalytic durability for 15 h. This work provides an opportunity for the design of excellent and robust MoS2-based catalyst via structural engineering and doping method.  相似文献   

13.
Hydrogen evolution reaction (HER) using transition metal dichalcogenides (TMDs) have gained interest owing to their low-cost, abundancy and predominant conductivity. However, forthright comparisons of transition metal chalcogenides for HER are scarcely conducted. In this work, we report the synthesis of series of molybdenum chalcogenide nanostructures MoX2 (X = S, Se, Te) via a facile hydrothermal method. Used as an electrocatalyst for HER, MoS2 nanograins, MoSe2 nanoflowers and MoTe2 nanotubes could afford the benchmark current densities of 10 mA cm−2 at the overpotentials of −173 mV, −208 mV and −283 mV with the measured Tafel slope values of 109.81 mV dec−1, 65.92 mV dec−1 and 102.06 mV dec−1, respectively. Besides other factors influencing HER, the role of electronic conductivity in HER of these molybdenum dichalcogenides are elucidated. In addition, the presented molybdenum dichalcogenides in this work are also complimented with robustness as determined from high-current density stability measurements.  相似文献   

14.
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   

15.
Electrocatalytic hydrogen evolution reaction (HER) is one of the green and effective method to produce clean hydrogen energy. However, the development of non-Pt HER catalysts with excellent catalytic activity and long-term stability still remains a great challenge. Herein, a vertically aligned core-shell structure material with hollow polypyrrole (PPy) nanowire as a core and Ru-doped MoS2 (Ru–MoS2) nanosheets as a shell is firstly reported as a highly efficient and ultra-stable catalyst for HER in alkaline solutions. Results indicate that Ru–MoS2@PPy catalyst demands a low overpotential of 37 mV at 10 mA cm?2. In addition, the overpotential at 100 mA cm?2 is 157 mV and it is almost unchanged after 40,000 cyclic voltammetry cycles. The existence of PPy core not only ensures the vertical growth of MoS2 nanosheets to expose more edge sites, but also promotes the rapid transfer of electrons, contributing to the improvement of catalytic activity. More importantly, the strong interface interaction between MoS2 and PPy prevents the collapse of the vertical structure of MoS2 sheets in the electrocatalytic process and greatly enhances the stability of catalysts, which offers an effective strategy to design and synthesize the HER catalysts with superior catalytic stability.  相似文献   

16.
Low-cost and highly efficient electrocatalysts are critical to advance the hydrogen production industry via water electrolysis in alkaline media. Molybdenum disulfide (MoS2) nanosheets as earth-abundant electrocatalyst became a star material due to its unique graphene-like layered structure favoring electron transfer for hydrogen evolution catalysis. However, its electrocatalytic activities greatly hindered by the poor conductivity and the fewer exposure of catalytically active edged sites. Herein, hierarchical ZnS@C@MoS2 core-shell nanostructures were designed by using a bottom-up strategy combined with a simple selective etching. The coexistence of semiconductor ZnS and defective porous carbonaceous shell as the core not only enhanced the electrical conductivity, but also separated and loaded the exfoliated MoS2 nanosheets which effectively proliferated the exposed catalytically active edge sites (Mo and S sites). Upon optimal conditions, hierarchical ZnS@C@MoS2 core-shell nanostructures gave an overpotential of 118 mV at 10 mA/cm2 with a Tafel slope value of 55.4 mV/dec and better cycling stability after 500 cycles during the alkaline HER process, superior to pristine MoS2.  相似文献   

17.
Developing an efficient and inexpensive electrocatalyst is of paramount importance for realizing the green hydrogen economy through electrocatalytic water splitting. Here, we demonstrated a facile large-scale, industrially viable binder-free synthesis of Zn-doped NiS electrocatalyst on bare nickel foam (NF) through a hydrothermal technique. The present catalyst, i.e., nickel sulfide (NiS) nanosheets on nickel foam with optimized doping of Zn atom (Zn–NiS-3), displays excellent catalytic efficacy for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). It requires an overpotential of 320 mV for OER at a current density of 50 mA cm−2 and an overpotential of 208 mV for HER at a current density of 10 mA cm−2. The water electrolyser device having Zn–NiS-3 electrocatalyst as both cathode and anode show excellent performance, requiring a cell voltage of only 1.71 V to reach a current density of 10 mA cm−2 in an alkaline media. The density functional theory (DFT) based calculations showed enhanced density of states near Fermi energy after Zn doping in NiS and attributed to the enhanced catalytic activities. Thus, the present study demonstrates that Zn–NiS-3@NF can be coined as a viable electrocatalyst for green hydrogen production.  相似文献   

18.
Activity and stability are the kernels of MoS2-based catalysts for hydrogen evolution reactions (HER). Here an intercalation-exfoliation nanocomposite (N–MoS2/AOCF) was designed and successfully synthesized through a facile polymer-solution intercalation method, and the molecular chains of amidoximated polyacrylonitrile (AOCF) with coordinating ability was intercalated into the preintercalated molybdenum disulfide (N–MoS2) nanosheets. The structure characterization demonstrated that N–MoS2 dispersed randomly with a small size and curly lamellar structure. Besides, the interlayer spacing enlarged significantly in the AOCF matrix. Furthermore, N–MoS2 nanosheets are tightly combined with AOCF via the coordination bonds between –OH and –NH2 of AOCF; therefore, the diverse active sites and good stability of N–MoS2/AOCF were attributable to the intense bonding effect, inducing desirable HER performance in acidic medium. Notably, the obtained electrocatalyst exhibited a low overpotential (176 mV at a current density of 10 mA/cm2), a small Tafel slope (51.08 mV/dec), and a large electric double-layer capacitance (39.98 mF/cm2).  相似文献   

19.
Developing highly active, stable and sustainable electrocatalysts for overall water splitting is of great importance to generate renewable H2 for fuel cells. Herein, we report the synthesis of electrocatalytically active, nickel foam-supported, spherical core-shell Fe-poly(tetraphenylporphyrin)/Ni-poly(tetraphenylporphyrin) microparticles (FeTPP@NiTPP/NF). We also show that FeTPP@NiTPP/NF exhibits efficient bifunctional electrocatalytic properties toward both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). Electrochemical tests in KOH solution (1 M) reveal that FeTPP@NiTPP/NF electrocatalyzes the OER with 100 mA cm−2 at an overpotential of 302 mV and the HER with 10 mA cm−2 at an overpotential of 170 mV. Notably also, its catalytic performance for OER is better than that of RuO2, the benchmark OER catalyst. Although its catalytic activity for HER is slightly lower than that of Pt/C (the benchmark HER electrocatalyst), it shows greater stability than the latter during the reaction. The material also exhibits electrocatalytic activity for overall water splitting reaction at a current density of 10 mA cm−2 with a cell voltage of 1.58 V, along with a good recovery property. Additionally, the work demonstrates a new synthetic strategy to an efficient, noble metal-free-coordinated covalent organic framework (COF)-based, bifunctional electrocatalyst for water splitting.  相似文献   

20.
The mixed metal dichalcogenides combination of WS2–MoS2 was coated onto Cu substrate by electroless NiMoP plating technique and the electrocatalytic hydrogen evolution reaction (HER) performance was investigated. The enhanced structural, morphological parameters and boosted electrocatalytic performance of the various metal-metal molar ratio of WS2–MoS2 onto NiMoP plate were identified under variable operating conditions and it was successfully evaluated by various characterization techniques. The well-defined crystalline nature, phase, particle size, structure, elemental analysis and surface morphology of prepared coatings were analyzed by FESEM, XRD, AFM and EDS mapping. The electrochemical analysis was performed using open circuit potential (OCP) analysis, chronoamperometry (CA), electrochemical impedance spectroscopy (EIS), Tafel curves, linear sweep voltammetry (LSV), cyclic voltammetry (CV) and polarization studies to find the activity of prepared electrocatalyst towards electrochemical hydrogen evolution reactions. The performance of bare NiMoP and WS2–MoS2/NiMoP plates were compared and found that the HER activity of NiMoP can be reinforced by composite incorporation through the synergic effect arises with in the catalytic system, which improves surface roughness and enhances the magnitude of electrocatalyst toward HER. The achievement of enhanced catalytic performance of coatings was authenticate by the kinetic parameters such as decreases in Tafel slope (98 mV dec?1), enhanced exchange current densities (9.32 × 10?4 A cm?2), and a lower overpotential. The consistent performance and durability of the catalyst were also investigated. The enhanced electrocatalytic activity of WS2–MoS2/NiMoP coatings increased with respect to the surface-active sites associated with combination of mixed dichalcogenides and the synergic effect arises in between different components present in the coating system. This work envisages the progressive strategies for the economical exploration of a novel WS2–MoS2/NiMoP water splitting catalyst used for large scale H2 generation. The prepared WS2–MoS2/NiMoP embedded Cu substrate possess high catalytic activity due to its least overpotential of 101 mV at a benchmark current density of 10 mA cm?2, which demonstrated the sustainable, efficient and promising electrocatalytic property of prepared catalyst towards HER under alkaline conditions.  相似文献   

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