Abstract
The discovery of moiré superlattices (MSLs) opened an era in the research of ‘twistronics’. Engineering MSLs and realizing unique emergent properties are key challenges. Herein, we ...demonstrate an effective synthetic strategy to fabricate MSLs based on mechanical flexibility of WS
2
nanobelts by a facile one-step hydrothermal method. Unlike previous MSLs typically created through stacking monolayers together with complicated method, WS
2
MSLs reported here could be obtained directly during synthesis of nanobelts driven by the mechanical instability. Emergent properties are found including superior conductivity, special superaerophobicity and superhydrophilicity, and strongly enhanced electro-catalytic activity when we apply ‘twistronics’ to the field of catalytic hydrogen production. Theoretical calculations show that such excellent catalytic performance could be attributed to a closer to thermoneutral hydrogen adsorption free energy value of twisted bilayers active sites. Our findings provide an exciting opportunity to design advanced WS
2
catalysts through moiré superlattice engineering based on mechanical flexibility.
Defect engineering is one of the effective strategies to optimize the physical and chemical properties of molybdenum disulfide (MoS
2
) to improve catalytic hydrogen evolution reaction (HER) ...performance. Dislocations, as a typical defect structure, are worthy of further investigation due to the versatility and sophistication of structures and the influence of local strain effects on the catalytic performance. Herein, this study adopted a low-temperature hydrothermal synthesis strategy to introduce numerous dislocation-strained structures into the in-plane and out-of-plane of MoS
2
nanosheets. Superior HER catalytic activity of 5.85 mmol·g
−1
·h
−1
under visible light was achieved based on the high-density dislocations and the corresponding strain field. This work paves a new pathway for improving the catalytic activity of MoS
2
via a dislocation-strained synergistic modulation strategy.
Molybdenum disulfide (MoS2) with low cost, high activity and high earth abundance has been found to be a promising catalyst for the hydrogen evolution reaction (HER), but its catalytic activity is ...considerably limited due to its inert basal planes. Here, through the combination of theory and experiment, we propose that doping Ni in MoS2 as catalyst can make it have excellent catalytic activity in different reaction systems. In the EY/TEOA system, the maximum hydrogen production rate of EY/Ni-Mo-S is 2.72 times higher than that of pure EY, which confirms the strong hydrogen evolution activity of Ni-Mo-S nanosheets as catalysts. In the lactic acid and Na2S/Na2SO3 systems, when Ni-Mo-S is used as co-catalyst to compound with ZnIn2S4 (termed as Ni-Mo-S/ZnIn2S4), the maximum hydrogen evolution rates in the two systems are 5.28 and 2.33 times higher than those of pure ZnIn2S4, respectively. The difference in HER enhancement is because different systems lead to different sources of protons, thus affecting hydrogen evolution activity. Theoretically, we further demonstrate that the Ni-Mo-S nanosheets have a narrower band gap than MoS2, which is conducive to the rapid transfer of charge carriers and thus result in multi-photocatalytic reaction systems with excellent activity. The proposed atomic doping strategy provides a simple and promising approach for the design of photocatalysts with high activity and stability in multi-reaction systems.
In this paper, doping Ni in MoS2 as catalyst can make it have excellent catalytic activity in different reaction systems. It has been proved that Ni-Mo-S nanosheet has strong hydrogen evolution activity as catalyst by combining theory and experiment. Display omitted
Molybdenum disulfide (MoS2), a typical two-dimensional transition metallic layered material, attracts tremendous attentions in the electrochemical energy storage due to its excellent physicochemical ...properties. However, with the deepening of the research and exploration of the lithium storage mechanism of these advanced MoS2-based anode materials, the complex reaction process influenced by internal and external factors hinders the exhaustive understanding of the lithium storage process. To design stable anode material with high performance, it is urgent to review the mechanisms of reported anode materials and summarize the related factors that influence the reaction processes. This review aims to dissect all possible side reactions during charging and discharging process, uncover internal and external factors inducing various anode reactions and finally put forward strategies of controlling high cycling capacity and super-stable lithium storage capability of MoS2. This review will be helpful to the design of MoS2-based lithium-ion batteries (LIBs) with excellent cycle performance to enlarge the application fields of these advanced electrochemical energy storage devices.
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Highlights
The main effects of deformation of flexible catalytic materials on the catalytic hydrogen evolution reaction performance are discussed, and a series of novel strategies to design highly ...active catalysts based on the mechanical flexibility of low-dimensional nanomaterials are summarized in detail.
This review provides a strategic choice for the rational design of low-cost and high-performance industrialized electrocatalysts.
Deformable catalytic material with excellent flexible structure is a new type of catalyst that has been applied in various chemical reactions, especially electrocatalytic hydrogen evolution reaction (HER). In recent years, deformable catalysts for HER have made great progress and would become a research hotspot. The catalytic activities of deformable catalysts could be adjustable by the strain engineering and surface reconfiguration. The surface curvature of flexible catalytic materials is closely related to the electrocatalytic HER properties. Here, firstly, we systematically summarized self-adaptive catalytic performance of deformable catalysts and various micro–nanostructures evolution in catalytic HER process. Secondly, a series of strategies to design highly active catalysts based on the mechanical flexibility of low-dimensional nanomaterials were summarized. Last but not least, we presented the challenges and prospects of the study of flexible and deformable micro–nanostructures of electrocatalysts, which would further deepen the understanding of catalytic mechanisms of deformable HER catalyst.
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•In situ oxygen-facilitated dynamic active-site generation on strained MoS2 during photo-catalytic hydrogen evolution.•Strained MoS2 nanosheets with O-doping shows high photocatalytic ...activity and excellent long-term durability.•The effects of O-doping and strain on the HER activity of MoS2 are well explained both theoretically and experimentally.
Molybdenum disulfide (MoS2) is considered as one of the most effective materials which can supersede the high cost and scarcity of metal platinum (Pt) for the hydrogen evolution reaction (HER). One road block lying in access to high catalytic performance of MoS2 emanates from the inert basal plane. To enable inert basal plane of flexible MoS2, we demonstrate an effective synthesis strategy via the progressive transformation of MoS2 to MoS2-xOx with O atomically dispersed under actual photo-catalytic hydrogen evolution condition. The rate of hydrogen production of new reconstructed MoS2-xOx nanosheets is improved to be much higher than that of the initial MoS2. Our theoretical calculation results indicate that the appropriate O substitution and strain could modulate the surface electronic state and optimize the Gibbs free energy (ΔGH) of MoS2, thus dramatically accelerating the catalytic efficiency. This work showcases a promising route to achieve tunable photochemical reconstruction by optimizing the electronic structure for low-cost and robust MoS2-based HER catalysts.
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•Physicochemical properties of MoS2 are regulated by spontaneous oxidation.•Excellent photo-catalytic activity is realized through spontaneous oxidation.•Performance-enhancing ...mechanism of the oxide-MoS2 is explained by DFT calculation.
Surface oxidation engineering has been regarded as a fascinating strategy to construct MoS2-based catalyst. However, it is still challenging to precisely control the oxidation degree of MoS2 to improve its photo-catalytic hydrogen evolution reaction (PHER) activity. In this work, we monitor the defect-driven spontaneous oxidation behavior of MoS2 in an aqueous solution to optimize the PHER performance of MoS2. After exposing to the ambient atmosphere for several weeks at room temperature, defective MoS2 in solution undergoes dramatic aging effects including morphology and component evolution. The oxide-MoS2 catalyst exhibits extraordinary PHER activity with 7.85 mmol g−1h−1 under dual xenon lamp, which is 3.25 times higher than of the prefect 2H-MoS2. The synergistic effect from optimized electronic structure, the intrinsic activity of the active sites and prominent photothermal effect of MoS2 with a certain degree of oxidation greatly enhances the photo-catalytic activity. This work provides a new pathway to control the physicochemical properties and catalytic performance of MoS2-based catalysts by the defect-driven selective oxidation.
Atom‐economic catalysts open a new era of computationally driven atomistic design of catalysts. Rationally manipulating the structures of the catalyst with atomic‐level precision would definitely ...play a significant role in the future chemical industry. Of particular concern, there are growing research concentrating on MoS2 as a typical representative of transition metal dichalcogenides for its great potential of diverse atomic‐level reactive sites for applications in catalysis for hydrogen evolution reaction. At present, the rational design of MoS2‐based catalysts greatly depends on the comprehensive understanding of its structure–activity relationships of active sites that still lacks the systematic summary. In this regard, we dissected the internal relationships between diverse active‐site configurations of MoS2 and the corresponding catalytic activity theoretically and experimentally to give impetus to the design of next‐generation high‐performance MoS2‐based catalysts. The necessity of normalizing the existing activity evaluation methodology and developing more‐precise metrics is discussed. Moreover, the advancement of artificial intelligence as an effective tool for the research on physicochemical properties of catalysts as well as its important role in theoretical pre‐design has also been reviewed. Finally, we summarized the opportunities and challenges of the design of nanoscale catalysts with desired physicochemical properties by assembling atoms in a controllable way.
The rational design of catalysts at the atomic level opens a new era for the research on next‐generation high‐performance catalysts. With an emphasis on the structure‐activity relationships of diverse existing and promising active sites, the progress in the design of MoS2‐based catalysts from the aspects of the experiment, theory, and AI modeling are systematically discussed.
Two‐dimensional (2D) transition‐metal dichalcogenides (TMDs) have emerged as promising catalysts for the hydrogen evolution reaction (HER) that play a crucial role in renewable energy technologies. ...Breaking the inherent structural paradigm limitations of 2D TMDs is the key to exploring their fascinating physical and chemical properties, which is expected to develop a revolutionary HER catalyst. Herein, we unambiguously present metallic W2S3 instead of energetically favorable WS2 via a unique stoichiometric growth strategy. Benefiting from the excellent conductivity and hydrophilicity of the tetra‐coordinated structure, as well as an appropriate Gibbs free energy value and an enough low energy barrier for water dissociation, the W2S3 as catalyst achieves Pt‐like HER activity and high long‐term stability in both acidic and alkaline electrolytes. For application in proton exchange membrane (PEM) and anion exchange membrane (AEM) electrolysers, W2S3 as the cathode catalyst yields excellent bifunctionality index (ɳ
@1Acm-2,PEM
${_{{\rm{@1 {\rm A} cm}}^{{\rm{ - }}{\rm{2}}} {\rm{, PEM}}} }$
=1.73 V, ɳ
@1Acm-2,AEM
${_{{\rm{@1 {\rm A} cm}}^{{\rm{ - }}{\rm{2}}} {\rm{, AEM}}} }$
=1.77 V) and long‐term stability (471 h@PEM with a decay rate of 85.7 μV h−1, 360 h@AEM with a decay rate of 27.1 μV h−1). Our work provides significant insight into the tetra‐coordinated W2S3 and facilitates the development of advanced electrocatalysts for sustainable hydrogen production.
A metallic tetra‐coordinated W2S3 crystal has been reported based on the theoretical structure prediction in combination with experimental results. For application in polymer electrolyte membrane (PEM) and anion exchange membrane (AEM) electrolysers, W2S3 as the cathode catalyst yields excellent bifunctionality index (ɳ@1Acm−2,PEM=1.73 V, ɳ@1Acm−2,AEM=1.77 V) and long‐term stability (471 h@PEM, 360 h@AEM).
•Introduce the nature of active sites of molybdenum sulfide-based catalysts for HER.•Summarize various HER mechanisms of a-MoSx.•Intensely discuss structure-performance relationship between the ...catalytic active sites and the catalytic activity of a-MoSx.•Review the challenges and potential opportunities of a-MoSx.
It is particularly important to investigate the structure–activity relationships between the catalytic active sites and the catalytic activity. Molybdenum sulfide has been widely studied as a representative transition metal dichalcogenides-based catalyst in the field of catalytic hydrogen evolution reaction (HER). The atomic structures of active sites of crystalline molybdenum disulfide are very unambiguous, while the catalytic HER mechanism of amorphous molybdenum sulfide (a-MoSx) has been controversial due to the diverse atomic structures of active sites in a-MoSx. It is urgent to find out the nature of true active sites of a-MoSx to further design efficient HER active sites with precise atomic structures. So far, the researchers have explored various HER mechanisms of a-MoSx combining in-situ characterization with density functional theory calculations. These mechanisms are not uniform or even diametrically opposed. Here, various HER mechanisms of a-MoSx were summarized systematically. In view of the current research status, the nature of active sites of molybdenum sulfide-based catalysts for HER is still difficult to determine. This review would be significant for further revealing the nature of active sites of molybdenum sulfide-based catalysts for HER.
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