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1.
Three‐Dimensional Structures of MoS2 Nanosheets with Ultrahigh Hydrogen Evolution Reaction in Water Reduction 
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下载免费PDF全文 Xiumei Geng Wei Wu Ning Li Weiwei Sun Johnathan Armstrong Alaa Al‐hilo Matthew Brozak Jingbiao Cui Tar‐pin Chen 《Advanced functional materials》2014,24(39):6123-6129
The hydrogen evolution reaction in an alkaline environment using a non‐precious catalyst with much greater efficiency represents a critical challenge in research. Here, a robust and highly active system for hydrogen evolution reaction in alkaline solution is reported by developing MoS2 nanosheet arrays vertically aligned on graphene‐mediated 3D Ni networks. The catalytic activity of the 3D MoS2 nanostructures is found to increase by 2 orders of magnitude as compared to the Ni networks without MoS2. The MoS2 nanosheets vertically grow on the surface of graphene by employing tetrakis(diethylaminodithiocarbomato)molybdate(IV) as the molybdenum and sulfur source in a chemical vapor deposition process. The few‐layer MoS2 nanosheets on 3D graphene/nickel structure can maximize the exposure of their edge sites at the atomic scale and present a superior catalysis activity for hydrogen production. In addition, the backbone structure facilitates as an excellent electrode for charge transport. This precious‐metal‐free and highly efficient active system enables prospective opportunities for using alkaline solution in industrial applications. 相似文献
2.
Jiadong Zhou Bijun Tang Junhao Lin Danhui Lv Jia Shi Linfeng Sun Qingsheng Zeng Lin Niu Fucai Liu Xiaowei Wang Xinfeng Liu Kazu Suenaga Chuanhong Jin Zheng Liu 《Advanced functional materials》2018,28(31)
In recent years, heterostructures formed in transition metal dichalcogenides (TMDs) have attracted significant attention due to their unique physical properties beyond the individual components. Atomically thin TMD heterostructures, such as MoS2‐WS2, MoS2‐MoSe2, MoS2‐WSe2, and WSe2‐WS2, are synthesized so far via chemical vapor deposition (CVD) method. Engineering the morphology of domains including size and shape, however, still remains challenging. Here, a one‐step CVD strategy on the morphology engineering of MoS2 and WS2 domains within the monolayer MoS2‐WS2 lateral heterostructures through controlling the weight ratio of precursors, MoO3 and WO3, as well as tuning the reaction temperature is reported. Not only can the size ratio in terms of area between WS2 and MoS2 domains be easily controlled from less than 1 to more than 20, but also the overall heterostructure size can be tuned from several to hundreds of micrometers. Intriguingly, the quantum well structure, a WS2 stripe embedded in the MoS2 matrix, is also observed in the as‐synthesized heterostructures, offering opportunities to study quantum confinement effects and quantum well applications. This approach paves the way for the large‐scale fabrication of MoS2‐WS2 lateral heterostructures with controllable domain morphology, and shall be readily extended to morphology engineering of other TMD heterostructures. 相似文献
3.
Novel and Enhanced Optoelectronic Performances of Multilayer MoS2–WS2 Heterostructure Transistors 下载免费PDF全文
下载免费PDF全文 Nengjie Huo Jun Kang Zhongming Wei Shu‐Shen Li Jingbo Li Su‐Huai Wei 《Advanced functional materials》2014,24(44):7025-7031
Van der Waals heterostructures designed by assembling isolated two‐dimensional (2D) crystals have emerged as a new class of artificial materials with interesting and unusual physical properties. Here, the multilayer MoS2–WS2 heterostructures with different configurations are reported and their optoelectronic properties are studied. It is shown that the new heterostructured material possesses new functionalities and superior electrical and optoelectronic properties that far exceed the one for their constituents, MoS2 or WS2. The vertical transistor exhibits a novel rectifying and bipolar behavior, and can also act as photovoltaic cell and self‐driven photodetector with photo‐switching ratio exceeding 103. The planar device also exhibits high field‐effect ON/OFF ratio (>105), high electron mobility of 65 cm2/Vs, and high photoresponsivity of 1.42 A/W compared to that in isolated multilayer MoS2 or WS2 nanoflake transistors. The results suggest that formation of MoS2–WS2 heterostructures could significantly enhance the performance of optoelectronic devices, thus open up possibilities for future nanoelectronic, photovoltaic, and optoelectronic applications. 相似文献
4.
Yu Zhou Cheng Li Yu Zhang Li Wang Xiulian Fan Luwei Zou Zhao Cai Jinming Jiang Shen Zhou Bo Zhang Hongyan Zhang Weihan Li Zhihui Chen 《Advanced functional materials》2023,33(46):2304302
As for 2D transition metal dichalcogenides, the creation of proper active defects concentrations is considered as the efficient strategy for improving hydrogen evolution performance. However, the synthesis methods of large-area MoS2 catalysts with controllable active defects are limited, also for its working mechanism. Herein, thermochemical generation of active defects for MoS2 catalysts has established by annealing sodium hypophosphite, in which the phosphine is spontaneously generated and chemically tailors the MoS2 lattice. The defects formation is confirmed by the investigation of slightly-changed surface structure and unpaired electrons for the annealed samples. The hydrogen evolution reaction performances of horizontally/vertically grown MoS2 films are improved by controlling reaction conditions, indicating the active defects could form in the basal plane and edges with retained crystal structure. The overpotential of MoS2 samples converted from 10 nm Mo reduces from −520 to −265 mV with largely decreased Tafel slope. The electrochemical microreactor studies reveal the protons adsorption of active sites shows much more significant contribution, than interfacial charge transfer with the enhanced remarkable performance (−100 mV at 10 mA cm−2). This study presents the large-area synthesized strategy for MoS2 based catalysts with controllable defects concentration and helps establish rational design principles for future MoS2 family electrocatalysts. 相似文献
5.
Shaohui Guo Xuanhua Li Xingang Ren Lin Yang Jinmeng Zhu Bingqing Wei 《Advanced functional materials》2018,28(32)
The design of transition‐metal chalcogenides (TMCs) photocatalysts for water splitting is highly important, in which both light absorption and interfacial engineering play vital roles in photoexcited electron generation, electron transport, and ultimately speeding up water splitting. To this end, plasmonic metal nanomaterials with surface plasmon resonances are promising candidates. However, it is very difficult to enhance the light absorption and manage the interfacial engineering simultaneously, thus, resulting in suboptimal photocatalytic performance. Here, a doped semiconductor plasmon is proposed to optically and electrically enhance TMCs hydrogen evolution. With the tunability of plasmon resonance in a doped MoO3 semiconductor via hydrogen reduction, the broadband absorption and good interfacial engineering are simultaneously demonstrated in flexible MoS2@MoO3 core–shell nanowire photocatalysts. Better energy‐band alignment with MoS2 can also be realized, thereby achieving improved photoinduced electron generation. More importantly, the defects at the interface between MoO3 and MoS2 are effectively reduced because of precise tunability of plasmon resonance, which enhances electron transport. As a proof of concept, this optimized hybrid nanostructure exhibits outstanding H2 evolution characteristics (841.4 μmol h?1 g?1), excellent stability, and good flexibility. The value is also one of the highest hydrogen evolution activity rates to date among the two dimensional‐layered visible‐light photocatalysts. 相似文献
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Xiaolei Huang Mei Leng Wen Xiao Meng Li Jun Ding Teck Leong Tan Wee Siang Vincent Lee Junmin Xue 《Advanced functional materials》2017,27(6)
Molybdenum disulfide (MoS2) has been considered as a promising alternative to platinum (Pt)‐based catalyst for hydrogen evolution reaction (HER) due to its low cost and high catalytic activity. However, stable 2H phase of MoS2 (2H‐MoS2) exhibits low catalytic activity in HER due to the inert basal plane and S‐edge. Thus, to exploit the basal plane and S‐edge for additional electrocatalytic activity, a facile strategy is developed to prepare P‐doped 2H‐MoS2 film on conductive substrate via low‐temperature heat treatment. Due to the inherent difficulty of P‐doping into MoS2 crystal structure, oxygen (O)‐doping is utilized to aid the P‐doping process, as supported by the first‐principles calculations. Interestingly, P‐doping could dramatically reduce Mo valence charge, which results in the functionalization of the inert MoS2 basal plane and S‐edge. In agreement with simulation results, P‐doped 2H‐MoS2 electrode exhibits enhanced catalytic performance in H2 generation with low onset potential (130 mV) and small Tafel slope of 49 mV dec?1. The enhanced catalytic performance arises from the synergistic effect of the activated basal plane, S‐edge, and Mo‐edge sites, leading to favorable hydrogen adsorption energies. Most importantly, improved cyclic stability is achieved, which reveals chemically inert properties of P‐doped 2H‐MoS2 in acidic electrolyte. 相似文献
8.
Yafei Cheng Shunkai Lu Fan Liao Liangbin Liu Yanqing Li Mingwang Shao 《Advanced functional materials》2017,27(23)
High overpotentials and low efficiency are two main factors that restrict the practical application for MoS2, the most promising candidate for hydrogen evolution catalysis. Here, Rh?MoS2 nanocomposites, the addition of a small amount of Rh (5.2 wt%), exhibit the superior electrochemical hydrogen evolution performance with low overpotentials, small Tafel slope (24 mV dec?1), and long term of stability. Experimental results reveal that 5.2 wt% Rh?MoS2 nanocomposite, even exceeding the commercial 20 wt% Pt/C when the potential is less than ?0.18 V, exhibits an excellent mass activity of 13.87 A mgmetal?1 at ?0.25 V, four times as large as that of the commercial 20 wt% Pt/C catalyst. The hydrogen yield of 5.2 wt% Rh?MoS2 nanocomposite is 26.3% larger than that of the commercial 20 wt% Pt/C at the potential of ?0.25 V. The dramatically improved electrocatalytic performance of Rh?MoS2 nanocomposites may be attributed to the hydrogen spillover from Rh to MoS2. 相似文献
9.
《Advanced functional materials》2017,27(23)
High overpotentials and low efficiency are two main factors that restrict the practical application for MoS2, the most promising candidate for hydrogen evolution catalysis. Here, Rh? MoS2 nanocomposites, the addition of a small amount of Rh (5.2 wt%), exhibit the superior electrochemical hydrogen evolution performance with low overpotentials, small Tafel slope (24 mV dec?1), and long term of stability. Experimental results reveal that 5.2 wt% Rh? MoS2 nanocomposite, even exceeding the commercial 20 wt% Pt/C when the potential is less than ?0.18 V, exhibits an excellent mass activity of 13.87 A mgmetal?1 at ?0.25 V, four times as large as that of the commercial 20 wt% Pt/C catalyst. The hydrogen yield of 5.2 wt% Rh? MoS2 nanocomposite is 26.3% larger than that of the commercial 20 wt% Pt/C at the potential of ?0.25 V. The dramatically improved electrocatalytic performance of Rh? MoS2 nanocomposites may be attributed to the hydrogen spillover from Rh to MoS2. 相似文献
10.
Bifunctional Electrocatalysts: Hierarchical NiCo2S4 Nanowire Arrays Supported on Ni Foam: An Efficient and Durable Bifunctional Electrocatalyst for Oxygen and Hydrogen Evolution Reactions (Adv. Funct. Mater. 26/2016) 下载免费PDF全文
下载免费PDF全文 Arumugam Sivanantham Pandian Ganesan Sangaraju Shanmugam 《Advanced functional materials》2016,26(26):4660-4660
11.
Arumugam Sivanantham Pandian Ganesan Sangaraju Shanmugam 《Advanced functional materials》2016,26(26):4661-4672
A recent approach for solar‐to‐hydrogen generation has been water electrolysis using efficient, stable, and inexpensive bifunctional electrocatalysts within strong electrolytes. Herein, the direct growth of 1D NiCo2S4 nanowire (NW) arrays on a 3D Ni foam (NF) is described. This NiCo2S4 NW/NF array functions as an efficient bifunctional electrocatalyst for overall water splitting with excellent activity and stability. The 3D‐Ni foam facilitates the directional growth, exposing more active sites of the catalyst for electrochemical reactions at the electrode–electrolyte interface. The binder‐free, self‐made NiCo2S4 NW/NF electrode delivers a hydrogen production current density of 10 mA cm–2 at an overpotential of 260 mV for the oxygen evolution reaction and at 210 mV (versus a reversible hydrogen electrode) for the hydrogen evolution reaction in 1 m KOH. This highly active and stable bifunctional electrocatalyst enables the preparation of an alkaline water electrolyzer that could deliver 10 mA cm–2 under a cell voltage of 1.63 V. Because the nonprecious‐metal NiCo2S4 NW/NF foam‐based electrodes afford the vigorous and continuous evolution of both H2 and O2 at 1.68 V, generated using a solar panel, they appear to be promising water splitting devices for large‐scale solar‐to‐hydrogen generation. 相似文献
12.
Jue Hu Chengxu Zhang Peng Yang Jingyi Xiao Tao Deng Zhiyong Liu Bolong Huang Michael K. H. Leung Shihe Yang 《Advanced functional materials》2020,30(6)
As a prerequisite for a sustainable energy economy in the future, designing earth‐abundant MoS2 catalysts with a comparable hydrogen evolution catalytic performance in both acidic and alkaline environments is still an urgent challenge. Decreasing the energy barriers could enhance the catalysts' activity but is not often a strategy for doing so. Here, the first kinetic‐oriented design of the MoS2‐based heterostructure is presented for pH‐universal hydrogen evolution catalysis by optimizing the electronic structure based on the simultaneous modulation of the 3d‐band‐offsets of Ni, Co, and Mo near the interface. Benefiting from this desirable electronic structure, the obtained MoS2/CoNi2S4 catalyst achieves an ultralow overpotential of 78 and 81 mV at 10 mA cm?2, and turnover frequency as high as 2.7 and 1.7 s?1 at the overpotential of 200 mV in alkaline and acidic media, respectively. The MoS2/CoNi2S4 catalyst represents one of the best hydrogen evolution reaction performing ones among MoS2‐based catalysts reported to date in both alkaline and acidic environments, and equally important is the remarkable long‐term stability with negligible activity loss after maintaining at 10 mA cm?2 for 48 h in both acid and base. This work highlights the potential to deeply understand and rationally design highly efficient pH‐universal electrocatalysts for future energy storage and delivery. 相似文献
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Developing efficient and economical electrocatalysts for hydrogen evolution reaction and oxygen evolution reaction with readily available metals is one of the main challenges for large scale hydrogen/oxygen production. This study reports one step synthesis of cobalt and molybdenum hybrid materials for high performance overall water splitting. The binder‐free CoS‐doped β‐Co(OH)2@amorphous MoS2+x is coated on nickel foam (NF) to form 3D networked nanoplates that have large surface area and high durability for electrochemical reactions. The catalytic activity of electrocatalyst for hydrogen evolution is mainly attributed to the unsaturated sulfur site of amorphous MoS2+x. Meanwhile, the CoS‐doped β‐Co(OH)2 plays the major role in oxygen evolution. CoS‐doped β‐Co(OH)2 and aMoS2+x are strongly bound to each other due to CoSx bridging. This CoS? Co(OH)2@aMoS2+x/NF hybrid exhibits excellent catalytic activity and stability for overall water splitting. For over 100 000 s the cell voltage required to achieve the current density of 10 mA cm–2 is only 1.58 V, which is remarkably low among the commercially available electrocatalysts. The findings open up an easy and inexpensive method of large scale fabrication of bifunctional electrocatalysts for overall water splitting. 相似文献
15.
Yuan Teng Xu‐Dong Wang Jin‐Feng Liao Wen‐Guang Li Hong‐Yan Chen Yu‐Jie Dong Dai‐Bin Kuang 《Advanced functional materials》2018,28(34)
Engineering non‐noble metal–based electrocatalysts with superior water oxidation performance is highly desirable for the production of renewable chemical fuels. Here, an atomically thin low‐crystallinity Fe–Mn–O hybrid nanosheet grown on carbon cloth (Fe–Mn–O NS/CC) is successfully synthetized as an efficient oxygen evolution reaction (OER) catalyst. The synthesis strategy involves a facile reflux reaction and subsequent low‐temperature calcination process, and the morphology and composition of hybrid nanosheets can be tailored conveniently. The defect‐rich Fe–Mn–O ultrathin nanosheet with uniform element distribution enables exposure of more catalytic active sites; moreover, the atomic‐scale synergistic action of Mn and Fe oxide contributes to an enhanced intrinsic catalytic activity. Therefore, the optimized Fe–Mn–O hybrid nanosheets, with lateral sizes of about 100–600 nm and ≈1.4 nm in thickness, enable a low onset potential of 1.46 V, low overpotential of 273 mV for current density of 10 mA cm?2, a small Tafel slope of 63.9 mV dec?1, and superior durability, which are superior to that of individual MnO2 and FeOOH electrode, and even outperforming most reported MnO2‐based electrocatalysts. 相似文献
16.
Junyong Wang Xin Luo Shisheng Li Ivan Verzhbitskiy Weijie Zhao Shunfeng Wang Su Ying Quek Goki Eda 《Advanced functional materials》2017,27(14)
Distorted octahedral T′ phase of MoTe2 has recently attracted significant interest due to its predicted topological states and novel charge transport properties. Here, we report a nondestructive method for determining the crystal orientation of few‐layer T′‐MoTe2 flakes by polarized Raman spectroscopy. The experimentally observed Raman modes are assigned to eigenmodes of vibrations predicted by density functional theory calculations. Polarized Raman measurements reveal four distinct types of angle‐dependent intensity variations. From group theory, it can be deduced that the intensity of the Bg mode reaches a maximum in the configuration when the polarization vector of the incident light is either parallel or orthogonal to the metal–metal zigzag chain direction. The intensity variation of the Bg mode cannot be used to unambiguously determine the crystal orientation. Using electron diffraction analysis, it is demonstrated that the intensity of the Ag mode at around 162 cm?1 reaches a maximum when the polarization vector of the incident light is parallel to the metal–metal chain direction in the configuration. Furthermore, a simple method is proposed for identifying crystal orientation in nonpolarized Raman spectroscopy. 相似文献
17.
J. Misiewicz K. Jezierski P. Sitarek P. Markiewicz R. Korbutowicz M. Panek B.
ciana M. T&#x;acza&#x;a 《Advanced functional materials》1995,5(6):321-327
Epitaxial undoped and doped (Si and Zn) GaAs and GaAIAs layers as well as heterostructures of GaAs/GaAIAs have been grown in an atmospheric pressure, vertical MOCVD system. Room temperature photoreflectance (PR) has been applied to characterise the layers and heterostructures as well as multiple quantum wells. The surface- and interface-related PR has been studied by application of Kramers–Kronig analysis. A decomposition of the PR spectrum into spectra connected with the surface region and with the interface has been proposed. 相似文献
18.
Patterned Growth: Patterned Growth of P‐Type MoS2 Atomic Layers Using Sol–Gel as Precursor (Adv. Funct. Mater. 35/2016) 下载免费PDF全文
下载免费PDF全文 Wei Zheng Junhao Lin Wei Feng Kai Xiao Yunfeng Qiu XiaoShuang Chen Guangbo Liu Wenwu Cao Sokrates T. Pantelides Wu Zhou PingAn Hu 《Advanced functional materials》2016,26(35):6495-6495
19.
Wei Zheng Junhao Lin Wei Feng Kai Xiao Yunfeng Qiu XiaoShuang Chen Guangbo Liu Wenwu Cao Sokrates T. Pantelides Wu Zhou PingAn Hu 《Advanced functional materials》2016,26(35):6371-6379
2D layered MoS2 has drawn intense attention for its applications in flexible electronic, optoelectronic, and spintronic devices. Most of the MoS2 atomic layers grown by conventional chemical vapor deposition techniques are n‐type due to the abundant sulfur vacancies. Facile production of MoS2 atomic layers with p‐type behavior, however, remains challenging. Here, a novel one‐step growth has been developed to attain p‐type MoS2 layers in large scale by using Mo‐containing sol–gel, including 1% tungsten (W). Atomic‐resolution electron microscopy characterization reveals that small tungsten oxide clusters are commonly present on the as‐grown MoS2 film due to the incomplete reduction of W precursor at the reaction temperature. These omnipresent small tungsten oxide clusters contribute to the p‐type behavior, as verified by density functional theory calculations, while preserving the crystallinity of the MoS2 atomic layers. The Mo containing sol–gel precursor is compatible with the soft‐lithography techniques, which enables patterned growth of p‐type MoS2 atomic layers into regular arrays with different shapes, holding great promise for highly integrated device applications. Furthermore, an atomically thin p–n junction is fabricated by the as‐prepared MoS2, which shows strong rectifying behavior. 相似文献
20.
From its inception, extensive work on the characterization of field effect transistors (FETs) based on 2D‐layered semiconductors has relied on a back‐gated transistor architecture. This is useful for initial assessment but lacks ultimate compatibility with integrated circuit (IC) design since the threshold voltage of individual devices cannot be controlled independently in order to achieve specific ON‐state and OFF‐state performance. Note that threshold engineering via gate electrostatics is inevitable for 2D semiconductors owing to the absence of comprehensive, reliable, and universal doping schemes. In recent years, several strategies are adopted for the gating of individual 2D‐FETs such as atomic layer deposition (ALD) of high‐k dielectrics, drop casting of ionic liquids, and deterministic transfer of insulating 2D hexagonal boron nitride. These techniques have their respective strengths and weaknesses. A facile, low‐temperature, scalable, and universally applicable fabrication scheme for dual‐gated monolayer 2D‐FETs is reported here, which is compatible with the back‐end‐of‐the‐line (BEOL) process flow of complementary metal oxide semiconductor (CMOS) technology, using hydrogen silsesquioxane (HSQ). HSQ is a negative tone resist that possesses dielectric properties similar to SiO2 when exposed to high electron beam irradiation and thermal curing and can produce features as small as 10 nm. 相似文献