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 40 毫秒
1.
Developing high-efficiency electrocatalysts viable for pH-universal hydrogen evolution reaction (HER) has attracted great interest because hydrogen is a promising renewable energy carrier for replacing fossil fuels. Herein, we present a facile strategy for fabricating ultra-fine Ru nanoparticles (NPs) decorated V2O3 on the carbon cloth substrates as efficient and stable pH-universal catalysts for HER. Benefiting from the metallic property and electronic conductivity of V2O3 matrix, the optimized hybrid (Ru/V2O3-CC) exhibits excellent HER activities in a wide pH range, achieving lower overpotentials of 184, 219, and 221 mV at 100 mA cm−2 in 0.5 M H2SO4, 1.0 M KOH and 1.0 M phosphate-buffered saline, respectively. Moreover, the electrode remains superior stability with negligible degradation after 5000 cyclic voltammetry scanning whether in acidic, alkaline or neutral media. Experimental results, combined with theoretical calculations, demonstrate that the interaction between Ru NPs and the support V2O3 induces the local electronic density diversity, allowing optimization of the adsorption energy of Ru towards hydrogen intermediate H1, thus favoring the HER process.  相似文献   

2.
Metal-organic framework's (MOF) shortcomings, such as poor conductivity, poor stability, and easy aggregation, impede its development in various application fields. Ni/Mo2C/Mo2TiC2Tx@NC, a high-performance electrocatalyst for hydrogen evolution reaction, was prepared by incorporating a Mo2TiC2Tx MXene conductive matrix into MOF (namely C–Y). The Ni/Mo2C/Mo2TiC2Tx@NC electrocatalyst demonstrates a remarkable HER ability with an overpotential of 105 and 134 mV and Tafel slope of 58 and 75 mV dec−1 at a current density of 10 mA cm−2 in 0.5 M H2SO4 and 1.0 M KOH, respectively. The outperformed HER activity of Ni/Mo2C/Mo2TiC2Tx@NC catalyst is ascribe to the introduction of conductive Mo2TiC2Tx MXene as a carrier to improve the poor conductivity of MOF, the synergistic effect of Ni and Mo2C nanoparticles, and the protective effect of the carbon layer. The work not only provides an experimental approach to address the problem of poor conductivity of MOF, but also provides a high-performance electrocatalyst for HER reactions. By utilizing MOFs and MXene as the precursor and the conducting carrier, our work provides some experimental reference for fabrication of multi-component inexpensive electrocatalysts.  相似文献   

3.
Seawater electrolysis has become an efficient method which makes full use of natural resources to produce hydrogen. However, it suffers high energy cost and chloride corrosion. Herein, we first present a Ni2P/Co(PO3)2/NF heterostructure in which Co(PO3)2 with the nano-rose morphology in-situ grown on the rough Ni2P/NF. The unique 3D nano-rose structure and the optimized electronic structure of the heterostructure enable Ni2P/Co(PO3)2/NF super-hydrophilic and super-aerophobic characteristics, and highly facilitate hydrogen evolution reaction (HER) kinetics in alkaline fresh water, alkaline seawater and even industrial wastewater at large current density, which is rarely reported. Significantly, at large current densities, Ni2P/Co(PO3)2/NF only requires overpotentials of 217 and 307 mV for HER to achieve 1000 mA cm−2 in alkaline fresh water and alkaline seawater, respectively, and requires an overpotential of 469 mV for HER to deliver 500 mA cm−2 in industrial wastewater. Furthermore, the overall seawater splitting system in the two-electrode electrolyzer only requires voltage of 1.98 V to drive 1000 mA cm−2, which also demonstrates significant durability to keep 600 mA cm−2 for at least 60 h. This study opens a new avenue of designing high efficiency electrocatalysts for hydrogen production at large current densities in alkaline seawater and industrial wastewater.  相似文献   

4.
The synthesis of cost-effective and high-performance electrocatalysts for water splitting is the main challenge in electrochemical hydrogen production. In this study, we adopted a high throughput method to prepare bi-metallic catalysts for oxygen/hydrogen evolution reactions (OER/HER). A series of Ni–Mo alloy electrocatalysts with tunable compositions were prepared by a simple co-sputtering method. Due to the synergistic effect between Ni and Mo, the intrinsic electrocatalytic activity of the Ni–Mo alloy electrocatalysts is improved, resulting in excellent HER and OER performances. The Ni90Mo10 electrocatalyst shows the best HER performance, with an extremely low overpotential of 58 mV at 10 mA cm?2, while the Ni40Mo60 electrocatalyst shows an overpotential of 258 mV at 10 mA cm?2 in OER. More significantly, the assembled Ni40Mo60//Ni90Mo10 electrolyzer only needs a cell voltage of 1.57 V to reach 10 mA cm?2 for overall water splitting.  相似文献   

5.
Delicate design and rapid development of low-cost, highly active, and perdurable pH-universal heterogenveous hydrogen evolution reaction (HER) electrocatalysts are demanding challenge in energy-conversion technologies. Herein, heterostructured CoP/MoO2 electrocatalyst was synthesized by employing MoO2 nanorods as framework for the growth of CoP nanoparticles. Owing to the fact that the effective interface of heterostructure can enhance electron transfer/mass diffusion and expose ample active sites, the CoP/MoO2 reveals eminent HER activities with favorable long-term stability in all pH electrolytes, overpotentials of 69, 78, and 165 mV in 0.5 M H2SO4, 1.0 M KOH, and 1.0 M PBS (phosphate-buffered solution) electrolytes were required for CoP/MoO2 to reach the current density of 10 mA cm?2. This work emphasizes that strategy of electronic structure engineering holds great promises in pH-universal HER electrocatalysts for energy storage and conversion.  相似文献   

6.
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   

7.
Developing low-cost and high efficient electrocatalysts for both oxygen and hydrogen evolution reaction in an alkaline electrolyte toward overall water splitting is still a significant challenge. Here, a novel hierarchically heterostructured catalyst composed of ultrasmall Mo2C and metallic Co nanoparticles confined within a carbon layer is produced by a facile phase separation strategy. During thermal reduction of CoMoO4 nanosheets in CO ambient, in-situ generated nanoscale Co and ultrafine Mo2C conformally encapsulated in a conductive carbon layer. In addition, some carbon nanotubes catalyzed by Co nanoparticles vertically grew on its surface, creating 3D interconnected electron channels. More importantly, the integrated C@Mo2C/Co nanosheets assembled into the hierarchical architecture, providing abundant active surface and retaining the structural integrity. Benefiting from such unique structure, the constructed hierarchical heterostructure shows low overpotentials of 280 mV and 145 mV to reach a current density of 10 mA cm−2 for OER and HER in an alkaline electrolyte. Furthermore, the symmetrical electrolyzer assembled with catalyst exhibits a small cell voltage of 1.67 V at 10 mA cm−2 in addition to outstanding durability, demonstrating the great potential as a high efficient bifunctional electrocatalyst for overall water splitting.  相似文献   

8.
Strongly coupled platinum-based transition-metal oxide/carbon hybrids and the development of quantum-dot structures of hybrid catalysts are cost-effective and maximize accessible active sites. However, a significant obstacle still exists for the rational proposal and simple synthesis of hybrid quantum-dot material catalysts. Herein, novel PtxMo1-xSiC quantum dots encapsulated in reduced graphene oxide (rGO) (PtxMo1-xSiC QDs @rGO) for catalyzing the hydrogen evolution reaction (HER) were fabricated through a simple solution-induced impregnation method. The optimized Pt5Mo95SiC QDs @rGO catalyst only require overpotentials of 18 mV and 25 mV to deliver current densities of 10 mA cm−2 and 250 mA cm−2 in acidic media, respectively. The synergistic effects of the inner PtxMo1-xSiC QDs networks and outer conductive rGO sheets that promote electron transfer are responsible for the outstanding HER performance. This work presents a novel method for producing an extremely effective HER catalyst for applications on large-scale.  相似文献   

9.
Metallic photoelectrocatalysts possess a wide light absorption range and the fast hydrogen evolution reaction (HER) kinetics, which can be used as the next generation of catalysts towards photoelectrocataytic HER. In this work, molybdenum nitride has been fabricated via an in-suit growth method on metal molybdenum substance (Mo3N2/Mo foil). The metallic and optical property of Mo3N2 was confirmed by the DFT calculations and experimental results from UV–visible absorption spectrum and valence X-ray photoelectron spectroscopy spectrum. Photocatalytic HER rate of Mo3N2 reached to 158.78 μmol h?1 g?1. Furthermore, Mo3N2–MoS2/Mo foil was prepared to improve photoelectrocatalytic performance. Herein, a suitable energy band alignment for Mo3N2–MoS2/Mo foil was proposed based on experiments and DFT calculations, and the formation of a heterojunction (Mo3N2–MoS2) effectively suppressed the recombination of photo-generated carriers. The results of photoelectrocatalytic experiments suggested that the photocurrent density of Mo3N2–MoS2/foil was effectively enhanced about 1.5 times than that of simplex Mo3N2/Mo foil. The electrochemical experiments (LSV and EIS) indicated that the metallic nature of Mo3N2 was also beneficial to electrocatalytic HER, and the overpotential of Mo3N2–MoS2/Mo foil at 10 mA cm?2 was ?173 mV. This work provides a potential candidate for photoelectrocatalytic electrodes.  相似文献   

10.
Developing non-precious metal catalysts for oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) is crucial for proton exchange membrane fuel cell (PEMFC), metal-air batteries and water splitting. Here, we report a in-situ simple approach to synthesize ultra-small sized transition metal carbides (TMCs) nanoparticles coupled with nitrogen-doped carbon hybrids (TMCs/NC, including WC/NC, V8C7/NC and Mo2C/NC). The TMCs/NC exhibit excellent ORR and HER performances in acidic electrolyte as bi-functional catalysts. The potential of WC/NC at the current density of 3.0 mA cm?2 for ORR is 0.814 V (vs. reversible hydrogen electrode (RHE)), which is very close to Pt/C (0.827 V), making it one of the best TMCs based ORR catalysts in acidic electrolyte. Besides, the TMCs/NC exhibit excellent performances toward HER, the Mo2C/NC only need an overpotential of 80 mV to drive the current density of 10 mA cm?2, which is very close to Pt/C (37 mV), making it the competitive alternative candidate among the reported non-precious metal HER catalysts.  相似文献   

11.
Developing the novel catalysts with an excellent performance of hydrogen generation is essential to facilitate the application of hydrogen evolution reaction (HER). Herein, a heterostructured cobalt phosphide/nickel phosphide/carbon cloth (CoP/Ni2P/CC) composite was fabricated via an interfacial engineering strategy to achieve the modification of CoP nanoleaf on Ni2P nanosheet skeleton supported by carbon cloth. By virtue of the unique heterostructure, abundant exposing active sites and the synergistic coupling effect of CoP and Ni2P nanoparticles, the elaborated CoP/Ni2P/CC composite exhibits a robust catalytic property. Among fabricated composites, the optimal CoP/Ni2P/CC-4 catalyst behaves an excellent HER performance at a wide pH range (overpotentials of 67, 71 and 95 mV to afford 10 mA cm?2 in 0.5 M H2SO4, 1 M KOH and 1 M PBS, respectively). The HER current density of this composite shows a negligible degradation after continuous test for 24 h. Charmingly, the HER process of this catalyst was innovatively applied to reduce graphene oxide, and thus exploiting the fabrication route of reduced graphene oxide (rGO). We are sure that this work will provide a firm guideline for the exploitation of pH-universal HER catalysts and the exploration of HER application.  相似文献   

12.
The development of cost-effective, highly efficient and stable electrocatalysts for alkaline water electrolysis at a large current density has attracted considerable attention. Herein, we reported a one-dimensional (1D) porous Mo2C/Mo2N heterostructured electrocatalyst on carbon cloth as robust electrode for large current hydrogen evolution reaction (HER). The MoO3 nanobelt arrays and urea were used as the metal and non-metal sources to fabricate the electrocatalyst by one-step thermal reaction. Due to the in-situ formed abundant high active interfaces and porous structure, the Mo2C/Mo2N electrocatalyst shows enhanced HER activity and kinetics, as exemplified by low overpotentials of 54, 73, and 96 mV at a current density of 10 mA cm?2 and small Tafel slopes of 48, 59 and 60 mV dec?1 in alkaline, neutral and acid media, respectively. Furthermore, the optimal Mo2C/Mo2N catalyst only requires a low overpotential of 290 mV to reach a large current density of 500 mA cm?2 in alkaline media, which is superior to commercial Pt/C catalyst (368 mV) and better than those of recently reported Mo-based electrocatalysts. This work paves a facile strategy to construct highly efficient and low-cost electrocatalyst for water splitting, which could be extended to fabricate other heterostructured electrocatalyst for electrocatalysis and energy conversion.  相似文献   

13.
Developing robust non-noble catalysts towards hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is vital for large-scale hydrogen production from electrochemical water splitting. Here, we synthesize Sn- and Fe-containing sulfides and oxyhydroxides anchored on nickel foam (SnFeSxOy/NF) using a solvothermal method, in which a heterostructure is generated between the sulfides and oxyhydroxides. The SnFeSxOy/NF exhibits low overpotentials of 85, 167, 249, and 324 mV at 10, 100, 500 and 1000 mA cm?2 for the HER, respectively, and a low overpotential of only 281 mV at 100 mA cm?2 for the OER. When it serves as both anode and cathode to assemble an electrolyzer, the cell voltage is only 1.69 V at 50 mA cm?2. The sulfides should be the efficient active species for the HER, while the oxyhydroxides are highly active for the OER. The unique sulfide/oxyhydroxide heterostructure facilitates charge transfer and lowers reaction barrier, thus promoting electrocatalytic processes.  相似文献   

14.
Mo2C, which has a unique electronic structure similar to the electronic structure of Pt, is considered as the material with the greatest potential to replace Pt as a catalyst for the electrocatalytic hydrogen evolution reaction (HER). However, Mo2C thin films have not attracted enough attention in the field of electrocatalysis. This work proposes a method for preparing Mo2C thin films as a catalyst for electrocatalytic HER through radiofrequency magnetron sputtering. The HER activity of the Mo2C thin film in acidic and alkaline media is studied by changing the deposition power of the Mo2C target and doping Ni for structural modification. Results show that increasing the deposition power of Mo2C can significantly enhance the HER activity of the films in acidic and alkaline media, and metal Ni doping can further enhance the HER activity of the Mo2C films. In an alkaline environment at a current density of 10 mA cm−2, the films demonstrate an overpotential of as low as 163 mV with a Tafel slope of 107 mV·dec−1. In acidic media, the films present the corresponding overpotential of 201 mV and a Tafel slope of as low as 96 mV·dec−1. Moreover, the Ni-doped Mo2C films have excellent HER stability. The synergy between doped Ni and Mo vacancies optimizes the strength of the Mo–H bond and the adsorption and desorption equilibrium of active H, thus enhancing HER kinetics. This work guides the possible structural design of Mo2C thin films for electrocatalytic HER.  相似文献   

15.
Bifunctional non-precious electrocatalysts with high performance are highly desired for renewable energy but remain challenging. Herein, a CoFeP/rGO heterostructure was rational developed based on the synergistic effect, including superior conductivity, increased catalytic active sites of rGO support and the regulated electron distribution of bimetallic phosphide. At a current of 10 mA cm?2, the CoFeP/rGO-2 composite exhibits excellent HER activity with low overpotentials of 101 mV and 76 mV in 1.0 M KOH and 0.5 M H2SO4 electrolyte, respectively. And highly active alkaline OER performance was provided with an overpotential of only 275 mV to reach a current density of 10 mA cm?2. By the way, the CoFeP/rGO-2 electrode showed a pleasured working voltage of 1.58 V for overall water splitting in alkaline environment. More importantly, the long term durability and higher stability of the catalysts demonstrated their feasibility of bimetallic phosphide/rGO system as bifunctional electrocatalysts.  相似文献   

16.
Developing efficient bifunctional catalysts for hydrogen and oxygen evolution reactions (HER/OER) has attracted great interest in hydrogen production from water splitting. In this work, a novel material of Mo-doped NiFex nanospheres on 3D graphene fibers (Mo-NiFex/3DGFs) has been successfully fabricated through a simple and cheap one-step electrodeposition method. The Mo-NiFex/3DGFs possessed ultra-high conductivity and specific surface area, greatly benefiting to electrocatalytic hydrolysis activity. And it was found that Fe element could obviously promote OER process, while Mo doping facilitated both OER and HER reactions. We proved that there existed synergetic roles between Fe and Mo element, which could realize the control of the electronic structure and optimize the adsorption/desorption of intermediates. And electrochemical tests showed that the Mo–Ni/3DGFs exhibited a relatively smaller overpotential of 109.9 mV for HER, while the Mo-NiFex/3DGFs presented better OER performance with an overpotential of 240.8 mV at the current density of 100 mA cm-2 in 1.0 M KOH. Finally, a system for overall water splitting constructed by Mo–Ni/3DGFs||Mo–NiFe0.68/3DGFs electrodes has a low cell voltage of 1.52 V at 10 mA cm?2 and long-term stability, exceeding most of literature results. Our findings provide insight into possibilities for the simple synthesis of high-performance and cheap catalysts, and laid the foundation for the practical application of transition metal catalysts.  相似文献   

17.
The development of Ni–Fe layered double hydroxide (NiFe LDH) catalysts for overall water splitting (OWS) is urgently required. NiFe LDHs are promising catalysts for the oxygen evolution reaction (OER). However, their hydrogen evolution reaction (HER) performance is restricted by slow kinetics. The construction of multiple types of active sites to simultaneously optimise the OER and HER performance is significant for OWS using NiFe LDHs. Hence, a Co-doped NiFe LDH electrocatalyst with dislocations and stacking faults was designed to modulate the electronic structure and generate multiple types of activity sites. The Co0.03-NiFe0.97 LDH catalyst only required overpotentials of 280 (50 mA cm−2, OER) and 170 mV (10 mA cm−2, HER). However, it reached a current density of 50 mA cm−2 at 1.53 V during OWS. Co0.03-NiFe0.97 LDHs could be stabilised for 140 h at 1.52 V. Furthermore, Co0.03-NiFe0.97 LDHs exhibited a higher electrocatalytic activity than commercial Raney nickel and Pt/C||IrO2 under industrial conditions. The significant specific surface area, high conductivity, and unique microstructures are the major factors contributing to the excellent OWS performance. This study suggests an efficient strategy for introducing microstructures to fabricate catalysts with high activity for application in OWS.  相似文献   

18.
The design and development of low-cost, abundant reserves, high catalytic activity and durability bifunctional electrocatalysts for water splitting are of great significance. Here, simple hydrothermal and hydrogen reduction methods were used to fabricate a uniform distribution of Fe-doped MoO2/MoO3 sheets with abundant oxygen vacancies and heterojunctions on etched nickel foam (ENF). The Fe– MoO2/MoO3/ENF exhibited a small overpotential of 36 mV at 10 mA cm−2 for hydrogen evolution reaction (HER), an excellent oxygen evolution reaction (OER) overpotential of 310 mV at 100 mA cm−2 and outstanding stabilities of 95 h and 120 h for the HER and OER, respectively. As both cathode and anode catalysts, the heterogeneously structured Fe– MoO2/MoO3/ENF required a low cell voltage of 1.57 V at 10 mA cm−2. Density functional theory (DFT) calculations show that Fe doping and MoO2/MoO3 heterojunctions can significantly reduce the band gap of the electrode, accelerate electron transport and reduce the potential barrier for water splitting. This work provides a new approach for designing metal ion doping and heterostructure formation that may be adapted to transition metal oxides for water splitting.  相似文献   

19.
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   

20.
Developing multielement doped carbon material (CM) is extremely meaningful due to the synergistic regulation on electronic and molecular structure, which can endow catalysts with high electrochemical properties. However, it is a challenging issue owing to the complex and difficult preparation process. Herein, a novel waste tires-derived Zn, S, N self-doped CM is prepared and used for efficiently electrocatalytic hydrogen evolution reaction (HER). The electronic state and molecular structure are effectively adjusted by forming C–N and C–S bonds in CM, and the Zn 3d configuration could participate in molecular orbital hybridization to produce the synergistic effect with regulation of N and S, thus improving the electrocatalytic HER activity. The obtained Zn, S, N self-doped CM requires only an overpotential of 50 mV at 10 mA cm?2, which is close to that of Pt/C (42 mV). The cell voltage of Zn, S, N self-doped CM || RuO2 electrolyze (1.31 V) at 10 mA cm?2 is much smaller than that of Pt/C || RuO2 (1.46 V). This work points out a promising strategy for the development of multielement doped CM applied in electrocatalytic HER and the efficiently resourceful utilization of waste tires.  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