Functional Micro/Nanoreactors for Nanospace‐Confined Migrations and Diffusions

Wang, Xinyao; Liu, Jian

doi:10.1002/cnma.202000289

Cited by 8 publications

(8 citation statements)

References 71 publications

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“…A major challenge is the deviation of key mechanistic pathways involving nucleation, growth, attachment, and ripening with only slight changes in the reaction conditions. − Bulk suspensions usually contain complex sets of solvents, ligands, and additives that continuously participate in the reaction and determine the fate of each step. , This in turn necessitates cumbersome optimization experiments designed to determine the specific conditions needed to obtain each target nanostructure of rather simple composition and often leads to poor yields, nonreproducibility, and narrow generalization scope. − In contrast, in traditional chemical metallurgy, SSRs can reliably synthesize a plethora of bulk-scale multielemental compositions of diverse inorganic materials having a variety of configurations and crystal phases, without the complications of using ligands and solvents. , With their potential to exert sophisticated nanostructural control (with respect to shape, sizes, and dimensions), SSRs can serve as excellent tools to design and synthesize next-generation, complex NMs with unique properties and applications. ,, However, in the absence of any liquid media (solvent), high temperatures (>300 °C) are usually required to induce atomic/ionic diffusion at solid–solid interfaces. , Such solvent-free “mix-and-heat” strategies are advantageous in achieving unique NMs with intermetallic compositions that are unattainable at low temperatures. However, these strategies are accompanied by the unwanted risks of thermally induced reshaping, interparticle sintering, and the evasion of diverse kinetic products. ,− Therefore, advanced SSRs that can exploit controllable nanoscale processes such as atomic diffusion, the Kirkendall effect, sintering, and surface modulation must be developed and utilized. ,− Using the nanospace-confinement SSR (NSC-SSR) strategy, reactants, intermediates, and products remain within a specific volume range of tens to hundreds of nanometers owing to their confinement in a thermally stable nanoshell. ,,, During the high-temperature thermal transformations, establishing a well-protected, confined environment not only overcomes the sintering problem and enhances the reaction rates through intimate proximity among only a few interacting reactants but also allows for better control of the unique nanostructural evolution process. ,, Moreover, NSC-SSRs enable the opportunity to observe, deconvolute, and control novel intricate nanoscale chemical phenomena that are impossible to investigate in bulk-scale systems. …”

Section: Ssrs For the Synthesis Of Nanomaterialsmentioning

confidence: 99%

“…However, these strategies are accompanied by the unwanted risks of thermally induced reshaping, interparticle sintering, and the evasion of diverse kinetic products. ,− Therefore, advanced SSRs that can exploit controllable nanoscale processes such as atomic diffusion, the Kirkendall effect, sintering, and surface modulation must be developed and utilized. ,− Using the nanospace-confinement SSR (NSC-SSR) strategy, reactants, intermediates, and products remain within a specific volume range of tens to hundreds of nanometers owing to their confinement in a thermally stable nanoshell. ,,, During the high-temperature thermal transformations, establishing a well-protected, confined environment not only overcomes the sintering problem and enhances the reaction rates through intimate proximity among only a few interacting reactants but also allows for better control of the unique nanostructural evolution process. ,, Moreover, NSC-SSRs enable the opportunity to observe, deconvolute, and control novel intricate nanoscale chemical phenomena that are impossible to investigate in bulk-scale systems. , Such a comprehensive mechanistic understanding of solid-state nanoscale chemistry can be utilized to advance SSRs toward synthesizing sophisticated multicomponent NMs and the possible isolation of stable intermediate nanostructures similar to the kinetically controlled products of solution-state syntheses. − Apart from synthesizing sintering-proof, simple mono- or intermetallic spherical shapes from embedded precursors, NSC-SSRs can offer greater morphological control (porous, hollow, concave, Janus, etc.) during the postsynthetic NC conversion process involving redox transformation, phase mixing/segregation, and other chemical changes embedded/enclosed within a suitable nanoscale medium. ,,− In this section, we attempt to categorize the different NSC-SSR strategies based on the nature of the space confinement, including precursors/NCs that are tightly embedded; confined in the hollow cavity, pores, and channels; or bound to the open solid support through lattice confinement.…”

Section: Ssrs For the Synthesis Of Nanomaterialsmentioning

confidence: 99%

“…Within the scope of NSC-SSR research to date, the major focus has been on SiO 2 nanospheres embedded with different metal ions and/or NCs, which are subjected to high-temperature (>500 °C) redox conditions. This has resulted in the synthesis/transformation of NCs with diverse morphologies, compositions, and interfaces through highly controlled processes such as NC migration, phase mixing/segregation, sintering, and hollowing. , Other confining media such as carbon shells and different metal oxides have also been utilized to accomplish similar transformations. − …”

Section: Ssrs For the Synthesis Of Nanomaterialsmentioning

confidence: 99%

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Solid-State Reaction Synthesis of Nanoscale Materials: Strategies and Applications

et al. 2022

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Nanomaterials (NMs) with unique structures and compositions can give rise to exotic physicochemical properties and applications. Despite the advancement in solution-based methods, scalable access to a wide range of crystal phases and intricate compositions is still challenging. Solid-state reaction (SSR) syntheses have high potential owing to their flexibility toward multielemental phases under feasibly high temperatures and solvent-free conditions as well as their scalability and simplicity. Controlling the nanoscale features through SSRs demands a strategic nanospace-confinement approach due to the risk of heat-induced reshaping and sintering. Here, we describe advanced SSR strategies for NM synthesis, focusing on mechanistic insights, novel nanoscale phenomena, and underlying principles using a series of examples under different categories. After introducing the history of classical SSRs, key theories, and definitions central to the topic, we categorize various modern SSR strategies based on the surrounding solid-state media used for nanostructure growth, conversion, and migration under nanospace or dimensional confinement. This comprehensive review will advance the quest for new materials design, synthesis, and applications.

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Section: Ssrs For the Synthesis Of Nanomaterialsmentioning

confidence: 99%

Section: Ssrs For the Synthesis Of Nanomaterialsmentioning

confidence: 99%

Section: Ssrs For the Synthesis Of Nanomaterialsmentioning

confidence: 99%

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Solid-State Reaction Synthesis of Nanoscale Materials: Strategies and Applications

et al. 2022

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“…As evidenced earlier, the metal ions diffused into the cavity space of the HSNTs through the porous silica shell. Therefore, the thickness should play an important role in the diffusivity of metal ions and the formation of metal nanostructures . Comparing the HSNTs made from sample C with sample D, both possessed a similar length ( L ) and inner diameter ( D ).…”

Section: Results and Discussionmentioning

confidence: 99%

“…Therefore, the thickness should play an important role in the diffusivity of metal ions and the formation of metal nanostructures. 38 Comparing the HSNTs made from sample C with sample D, both possessed a similar length (L) and inner diameter (D).…”

Section: ■ Introductionmentioning

confidence: 99%

Hollow Silica Nanotubes for Space-Confined Synthesis of Noble Metal Nanorods and Nanopeapods

Chen

Xie

Wang

et al. 2021

ACS Appl. Nano Mater.

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Realizing precise control over the size and functionality of nanomaterials is a prerequisite to their diverse applications in the areas of biology, environment, energy, and other emerging nanotechnologies. Herein, we demonstrate a general template strategy capable of fabricating functional noble metallic nanorods and nanopeapods. The templates are hollow silica nanotubes (HSNTs) produced from unimolecular micelles of bottlebrush copolymers. The variation of chain length and chemical composition of bottlebrush copolymers achieved through the reversible-deactivation radical polymerization dictates the length (L), inner diameter (D), and thickness (h) of HSNTs. Using such HSNTs as nanoreactors enables the fabrication of noble metals such as Au, Ag, and Pt nanorods or nanopeapods with silica shells in a space-confined manner. While the thickness and the interior space of HSNTs regulate the diffusion and intake of metal ion precursors, the formation of nanorods or nanopeapods with different lengths and diameters is well controlled. Upon etching out the silica shell, the resulting metallic nanorods are readily functionalized with polymeric ligands for excellent dispersity in aqueous and/or organic media. This feasible and versatile strategy represents a great leap forward in the controlled synthesis of onedimensional metallic nanomaterials and hopefully promotes understanding their structure-determined physiochemical properties and board applications in medicine and catalysis.

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Silica Jar‐with‐Lid as Chemo‐Enzymatic Nano‐Compartment for Enantioselective Synthesis inside Living Cells

et al. 2021

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Nanodevices, harvesting the power of synthetic catalysts and enzymes to perform enantioselective synthesis inside cell, have never been reported. Here, we synthesized round bottom jar-like silica nanostructures (SiJARs) with a chemo-responsive metal-silicate lid. This was isolated as an intermediate structure during highly controlled solid-state nanocrystal-conversion at the arc-section of silica shell. Different catalytic noble metals (Pt, Pd, Ru) were selectively modified on the lid-section through galvanic reactions. And, lid aperture-opening was regulated by mild acidic conditions or intracellular environment which accommodated the metal nanocrystals and enzymes, and in turn created an openmouth nanoreactor. Distinct from the free enzymes, SiJARs performed asymmetric aldol reactions with high activity and enantioselectivity (yield > 99 %, ee = 95 %) and also functioned as the artificial catalytic organelles inside living cells. This work bridges the enormous potential of sophisticated nanocrystal-conversion chemistry and advanced platforms for new-to-nature catalysis.Evolutionary compartmentalization is the key structural feature of various organelles and cells to accommodate specific enzymes and cofactors, which effortlessly drive lifesustaining multistep biochemical cascades. [1] artificial organelle-like nanoreactors harnessing high activity of synthetic catalysts along with inherent handedness of enzymes, can result diversified platforms for bioorthogonal synthesis. [2, 3] These chemo-enzymatic systems can asymmetrically synthesize chiral enantiomeric bioactive molecules, [4] possessing distinct pharmacological and toxicological systemic responses and in turn leading to advanced bioimaging, therapeutic and biotechnological applications. [5] Variety of nature-inspired hollow nanostructures, which consist of silica/silicate [4b,c, 6] and polymers/micelles [3a, 7] confining catalytic nanocrystals (NCs), enzymes or both, have demonstrated improved catalysis that are mostly limited to abiotic conditions. [8] Microemulsion-, sacrificial template-, and one-pot entrapment-based methods for pre-encapsulation of bio/nano-catalysts inside a confining nano-housing, often involve difficult to control multiple synthetic steps, harsh conditions, biphasic non-aqueous solvents and complex reagents. [9] Major challenge to design nanoreactors for intracellular application is to reliably colocalize and maintain the reactive surfaces of catalytic NCs along with the protection of enzymes from de-activation. [4,10] In this regard, silica nanostructures are highly appealing for wide range of catalytic and biomedical applications owing to their chemical inertness, high stability, biocompatibility and synthetic flexibility. [11] Previously, we developed solid-state conversion strategy for reversible hollowing of silica-coated manganese oxide (MnO@SiO 2 ) [12] and the post-synthetic modification of the hollow silica interiors with catalytic noble metals. [13] However, these microporous closed shells restrict the entry and co-...

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Functional Micro/Nanoreactors for Nanospace‐Confined Migrations and Diffusions

Cited by 8 publications

References 71 publications

Solid-State Reaction Synthesis of Nanoscale Materials: Strategies and Applications

Solid-State Reaction Synthesis of Nanoscale Materials: Strategies and Applications

Hollow Silica Nanotubes for Space-Confined Synthesis of Noble Metal Nanorods and Nanopeapods

Silica Jar‐with‐Lid as Chemo‐Enzymatic Nano‐Compartment for Enantioselective Synthesis inside Living Cells

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