As one member of the emerging class of ultrathin two‐dimensional (2D) transition‐metal dichalcogenide (TMD) nanomaterials, the ultra‐thin MoS2 nanosheet has attracted increasing research interest as ...a result of its unique structure and fascinating properties. Solution‐phase methods are promising for the scalable production, functionalization, hybridization of MoS2 nanosheets, thus enabling the widespread exploration of MoS2‐based nanomaterials for various promising applications. In this Review, an overview of the recent progress of solution‐processed MoS2 nanosheets is presented, with the emphasis on their synthetic strategies, functionalization, hybridization, properties, and applications. Finally, the challenges and opportunities in this research area will be proposed.
Sheets ahead: Solution‐based methods offer an effective route for the preparation of MoS2 nanosheets. With the an emphasis on applications, the synthetic strategies and methods for functionalization and hybridization are discussed.
Ultrathin two‐dimensional (2D) layered transition metal dichalcogenides (TMDs), such as MoS2, WS2, TiS2, TaS2, ReS2, MoSe2 and WSe2, have attracted considerable attention over the past six years ...owing to their unique properties and great potential in a wide range of applications. Aiming to achieve tunable properties and optimal application performances, great effort is devoted to the exploration of 2D multinary layered metal chalcogenide nanomaterials, which include ternary metal chalcogenides with well‐defined crystal structures, alloyed TMDs, heteroatom‐doped TMDs and 2D metal chalcogenide heteronanostructures. These novel 2D multinary layered metal chalcogenide nanomaterials exhibit some unique properties compared to 2D binary TMD counterparts, thus holding great promise in various potential applications including electronics/optoelectronics, catalysis, sensors, biomedicine, and energy storage and conversion with enhanced performances. This article focuses on the state‐of‐art progress on the preparation, characterization and applications of ultrathin 2D multinary layered metal chalcogenide nanomaterials.
The exploration of 2D multinary layered metal chalcogenide nanomaterials garners great efforts, aiming to achieve tunable properties and optimal application performances. State‐of‐the‐art progress on the preparation and characterization of ultrathin 2D multinary layered metal chalcogenide nanomaterials is reviewed, along with their potential application in electronics/optoelectronics, catalysis, sensors, biomedicine, and energy storage and conversion.
Phase has emerged as an important structural parameter - in addition to composition, morphology, architecture, facet, size and dimensionality - that determines the properties and functionalities of ...nanomaterials. In particular, unconventional phases in nanomaterials that are unattainable in the bulk state can potentially endow nanomaterials with intriguing properties and innovative applications. Great progress has been made in the phase engineering of nanomaterials (PEN), including synthesis of nanomaterials with unconventional phases and phase transformation of nanomaterials. This Review provides an overview on the recent progress in PEN. We discuss various strategies used to synthesize nanomaterials with unconventional phases and induce phase transformation of nanomaterials, by taking noble metals and layered transition metal dichalcogenides as typical examples. Moreover, we also highlight recent advances in the preparation of amorphous nanomaterials, amorphous-crystalline and crystal phase-based hetero-nanostructures. We also provide personal perspectives on challenges and opportunities in this emerging field, including exploration of phase-dependent properties and applications, rational design of phase-based heterostructures and extension of the concept of phase engineering to a wider range of materials.
The exploration of new porous hybrid materials is of great importance because of their unique properties and promising applications in separation of materials, catalysis, etc. Herein, for the first ...time, by integration of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), a new type of MOF@COF core–shell hybrid material, i.e., NH2‐MIL‐68@TPA‐COF, with high crystallinity and hierarchical pore structure, is synthesized. As a proof‐of‐concept application, the obtained NH2‐MIL‐68@TPA‐COF hybrid material is used as an effective visible‐light‐driven photocatalyst for the degradation of rhodamine B. The synthetic strategy in this study opens up a new avenue for the construction of other MOF–COF hybrid materials, which could have various promising applications.
By integration of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), a new type of MOF@COF core–shell hybrid material, i.e., NH2‐MIL‐68@TPA‐COF, with high crystallinity and hierarchical pore structure, is synthesized. The obtained hybrid material can be used as an effective visible‐light‐driven photocatalyst for the degradation of rhodamine B.
Noble‐metal nanomaterials are attracting increasing research interest due to their promising applications in electrochemical catalysis, for example. Although great efforts have been devoted to the ...size‐, shape‐, and architecture‐controlled synthesis of noble‐metal nanomaterials, their crystal‐phase‐controlled synthesis is still in its infancy. Here, for the first time, this study reports high‐yield synthesis of Au nanorods (NRs) with alternating 4H/face‐centered cubic (fcc) crystal‐phase heterostructures via a one‐pot wet‐chemical method. The coexistence of 4H and fcc phases is relatively stable, and the 4H/fcc Au NRs can serve as templates for crystal‐phase‐controlled epitaxial growth of other metals. As an example, bimetallic 4H/fcc Au@Pd core–shell NRs are synthesized via the epitaxial growth of Pd on 4H/fcc Au NRs. Significantly, the 4H/fcc Au@Pd NRs show superior mass activity toward the ethanol oxidation reaction, i.e., 6.2 and 4.9 times those of commercial Pd black and Pt/C catalysts, respectively. It is believed that this new synthetic strategy can be used to prepare other novel catalysts for various promising applications.
High‐yield crystal‐phase‐heterostructured 4H/fcc Au@Pd core–shell nanorods are successfully synthesized via a one‐pot, facile, wet‐chemical method. By using the 4H/fcc Au nanorod as a template, a 4H/fcc Au@Pd nanorod with epitaxially grown Pd shell is prepared, which exhibits superior electrocatalytic performance toward the ethanol oxidation reaction.
The ability to prepare ultrathin two-dimensional (2D) covalent organic framework (COF) nanosheets (NSs) in high yield is of great importance for the further exploration of their unique properties and ...potential applications. Herein, by elaborately designing and choosing two flexible molecules with C 3v molecular symmetry as building units, a novel imine-linked COF, namely, TPA-COF, with a hexagonal layered structure and sheet-like morphology, is synthesized. Since the flexible building units are integrated into the COF skeletons, the interlayer stacking becomes weak, resulting in the easy exfoliation of TPA-COF into ultrathin 2D NSs. Impressively, for the first time, the detailed structural information, i.e., the pore channels and individual building units in the NSs, is clearly visualized by using the recently developed low-dose imaging technique of transmission electron microscopy (TEM). As a proof-of-concept application, the obtained ultrathin COF NSs are used as a novel fluorescence sensing platform for the highly sensitive and selective detection of DNA.
Inspired by the multiple functions of natural multienzyme systems, a new kind of hybrid nanosheet is designed and synthesized, i.e., ultrasmall Au nanoparticles (NPs) grown on 2D metalloporphyrinic ...metal‐organic framework (MOF) nanosheets. Since 2D metalloporphyrinic MOF nanosheets can act as the peroxidase mimics and Au NPs can serve as artificial glucose oxidase, the hybrid nanosheets are used to mimic the natural enzymes and catalyze the cascade reactions. Furthermore, the synthesized hybrid nanosheets are used to detect biomolecules, such as glucose. This study paves a new avenue to design nanomaterial‐based biomimetic catalysts with multiple complex functions.
Inspired by the multiple functions of natural multienzyme systems, hybrid nanosheets are designed and synthesized, i.e., ultrasmall Au nanoparticles are grown on 2D metalloporphyrinic metal‐organic framework nanosheets. Since nanosheets can act as the peroxidase mimics and Au nanoparticles can serve as artificial glucose oxidase, the hybrid nanosheets are used to mimic the natural enzymes and catalyze the cascade reactions.
Despite unique properties of layered transition‐metal dichalcogenide (TMD) nanosheets, there is still lack of a facile and general strategy for the preparation of TMD nanodots (NDs). Reported herein ...is the preparation of a series of TMD NDs, including TMD quantum dots (e.g. MoS2, WS2, ReS2, TaS2, MoSe2 and WSe2) and NbSe2 NDs, from their bulk crystals by using a combination of grinding and sonication techniques. These NDs could be easily separated from the N‐methyl‐2‐pyrrolidone when post‐treated with n‐hexane and then chloroform. All the TMD NDs with sizes of less than 10 nm show a narrow size distribution with high dispersity in solution. As a proof‐of‐concept application, memory devices using TMD NDs, for example, MoSe2, WS2, or NbSe2, mixed with polyvinylpyrrolidone as active layers, have been fabricated, which exhibit a nonvolatile write‐once‐read‐many behavior. These high‐quality TMD NDs should have various applications in optoelectronics, solar cells, catalysis, and biomedicine.
On the dot: The title nanodots (NDs), including MoS2, WS2, ReS2, TaS2, MoSe2, WSe2, and NbSe2, are prepared from their bulk crystals by using a combination of grinding and sonication techniques. The synthesized nanodots, mixed with polyvinylpyrrolidone, are used as active layers for fabrication of memory devices having a nonvolatile memory effect. TMD=transition‐metal dichalcogenides.
Five‐fold‐twinned PtCu nanoframes (NFs) with nanothorns protruding from their edges are synthesized by a facile one‐pot method. Compared to commercial Pt/C catalyst, the obtained highly anisotropic ...five‐fold‐twinned PtCu NFs show enhanced electrocatalytic performance toward the oxygen reduction reaction and methanol oxidation reaction under alkaline conditions.
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