Beyond conventional porous materials, metal–organic frameworks (MOFs) have aroused great interest in the construction of nanocatalysts with the characteristics of catalytically active nanoparticles ...(NPs) confined into the cavities/channels of MOFs or surrounded by MOFs. The advantages of adopting MOFs as the encapsulating matrix are multifold: uniform and long‐range ordered cavities can effectively promote the mass transfer and diffusion of substrates and products, while the diverse metal nodes and tunable organic linkers may enable outstanding synergy functions with the encapsulated active NPs. Herein, some key issues related to MOFs for catalysis are discussed. Then, state‐of‐the art progress in the encapsulation of catalytically active NPs by MOFs as well as their synergy functions for enhanced catalytic performance in the fields of thermo‐, photo‐, and electrocatalysis are summarized. Notably, encapsulation‐structured nanocatalysts exhibit distinct advantages over conventional supported catalysts, especially in terms of the catalytic selectivity and stability. Finally, challenges and future developments in MOF‐based encapsulation‐structured nanocatalysts are proposed. The aim is to deliver better insight into the design of well‐defined nanocatalysts with atomically accurate structures and high performance in challenging reactions.
Compared with conventional supported catalysts, controllable encapsulation of catalytically active nanoparticles by porous metal–organic frameworks can exhibit intriguing features, such as uniform catalytic interface, strong interactions, the pore confinement effect, high stability, and outstanding designability, all of which contribute to the design and construction of high‐performance nanocatalysts.
Controllable integration of noble metals (e.g., Au, Ag, Pt, and Pd) and metal oxides (e.g., TiO₂, CeO₂, and ZrO₂) into single nanostructures has attracted immense research interest in heterogeneous ...catalysis, because they not only combine the properties of both noble metals and metal oxides, but also bring unique collective and synergetic functions in comparison with single-component materials. Among many strategies recently developed, one of the most efficient ways is to encapsulate and protect individual noble metal nanoparticles by a metal oxide shell of a certain thickness to generate the core-shell or yolk-shell structure, which exhibits enhanced catalytic performance compared with conventional supported catalysts. In this review article, we summarize the state-of-the art progress in synthesis and catalytic application of noble metal nanoparticle@metal oxide core/yolk-shell nanostructures. We hope that this review will help the readers to obtain better insight into the design and application of well-defined nanocomposites in both the energy and environmental fields.
Controllable integration of inorganic nanoparticles (NPs) and metal–organic frameworks (MOFs) is leading to the creation of many new multifunctional materials. In this Research News, an emerging type ...of core–shell nanostructure, in which the inorganic NP cores are encapsulated by the MOF shells, is briefly introduced. Unique functions originating from the property synergies of different types of inorganic NP cores and MOF shells are highlighted, and insight into their future development is suggested. It is highly expected that this Research News could arouse research enthusiasm on such NP@MOF core–shell nanostructures, which have great application potential in devices, energy, the environment, and medicine.
Controllable integration of inorganic nanoparticles (NPs) and metal–organic frameworks (MOFs) is creating many new multi‐functional materials. In this Research News, an emerging type of core–shell nanostructure, in which NP cores are encapsulated by MOF shells, is briefly introduced. The unique functions originating from property synergies of different types of NPs and MOFs are highlighted, and insights into their future development are offered.
Chiral colloidal semiconductor nanocrystals (NCs) are an emerging type of chiral materials. These chiral NCs exhibit unique quantum confinement-determined optical activity and have aroused much ...interest in the multidisciplinary fields of chemistry, physics and biology. Herein, the state-of-the-art progresses of their rational synthesis, fundamental understanding and potential application are summarized. In addition, a personal view about the future development of chiral semiconductor NCs is offered.
The unique capability of magnetic circular dichroism (MCD) in revealing geometry and electronic information has provided new opportunities in exploring the relationship between structure and ...magneto‐optical properties in nanomaterials with extraordinary optical absorption. Here, the representative studies referring to application of the MCD technique in semiconductor and noble metal nanomaterials are overviewed. MCD is powerful in elucidating the structural information of the excitonic transition in semiconductor nanocrystals, electronic transitions in noble metal nanoclusters, and plasmon resonance in noble metal nanostructures. By virtue of these advantages, the MCD technique shows its unrivalled ability in evaluating the magnetic modulation of excitonic and plasmonic optical activity of nanomaterials with varied chemical composition, geometry, assembly conformation, and coupling effect. Knowledge of the key factors in manipulating magneto‐optical properties at the nanoscale acquired with the MCD technique will largely boost the application of semiconductor and noble nanomaterials in the fields of sensing, spintronic, nanophotonics, etc.
Magnetic circular dichroism shows indispensable capability in elucidating the Zeeman splitting of the excitonic transition in semiconductor nanocrystals, the electronic information of discrete optical transitions in noble metal nanoclusters, and the geometry modulation of plasmon resonance in noble metal nanostructures. Key strategies in designing magneto‐optically active advanced nanomaterials are highlighted for potential applications in fields of sensing, spintronics, and nanophotonics.
Non-Pt noble metal clusters like Au clusters are believed to be promising high performance catalysts for the oxygen reduction reaction (ORR) at the cathode of fuel cells, but they still suffer big ...problems during the catalysis reactions, such as a large amount of the capping agents being on the surface and easy occurrence of dissolution and aggregation. To overcome these obstacles, here, we present a novel and general strategy to grow ultrafine Au clusters and other metal (Pt, Pd) clusters on the reduced graphene oxide (rGO) sheets without any additional protecting molecule or reductant. Compared with the currently generally adopted nanocatalysts, including commercial Pt/C, rGO sheets, Au nanoparticle/rGO hybrids, and thiol-capped Au clusters of the same sizes, the as-synthesized Au cluster/rGO hybrids display an impressive eletrocatalytic performance toward ORR, for instance, high onset potential, superior methanol tolerance, and excellent stability.
Complex and well‐defined nanostructures are promising for emerging properties with broad applications. Self‐assembly processes driven by diverse interactions generate varied nanostructures by using ...versatile nanocrystals as building blocks, while oriented attachment growth allows individual nanocrystals to be integrated and fused into highly anisotropic structures. By a combination of self‐assembly technique and oriented attachment growth, many advanced nanostructures can be made. Such approaches can be viewed as an architecture of the nanoscale counterparts in the microworld, named as nanoarchitectures.
Oriented self‐assembly is a novel nanoarchitecture approach for advanced nanostructure fabrication. Combining self‐assembly and oriented attachment, highly anisotropic nanostructures can be designed and made with diverse yet tunable properties. This approach opens opportunities for various applications.
Nacre (mother-of-pearl), made of inorganic and organic constituents (95 vol% aragonite calcium carbonate (CaCO(3)) platelets and 5 vol% elastic biopolymers), possesses a unique combination of ...remarkable strength and toughness, which is compatible for conventional high performance materials. The excellent mechanical properties are related to its hierarchical structure and precisely designed organic-inorganic interface. The rational design of aragonite platelet strength, aspect ratio of aragonite platelets, and interface strength ensures that the strength of nacre is maximized under platelet pull-out failure mode. At the same time, the synergy of strain hardening mechanisms acting over multiple scales results in platelets sliding on one another, and thus maximizes the energy dissipation of viscoplastic biopolymers. The excellent integrated mechanical properties with hierarchical structure have inspired chemists and materials scientists to develop biomimetic strategies for artificial nacre materials. This critical review presents a broad overview of the state-of-the-art work on the preparation of layered organic-inorganic nanocomposites inspired by nacre, in particular, the advantages and disadvantages of various biomimetic strategies. Discussion is focused on the effect of the layered structure, interface, and component loading on strength and toughness of nacre-mimic layered nanocomposites (148 references).
Self‐assembly of inorganic nanoparticles (NPs) into superstructures, which is used as a general way to integrate functional inorganic NPs into macroscale devices, has attracted much research ...interest. This review will summarize the recent progress and discuss future challenges of the inorganic NP superstructures. Examples include both DNA‐based and polymer‐based NP assemblies with controlled positioning and geometries, and quasicrystalline ordered structures from the self‐assembly of binary or ternary NPs. Different from their individual NP counterparts, these self‐assembled superstructures possess unique properties, such as optical chirality and dynamic structural change under an external stimulus. Due to their diversified structures and functionalities, inorganic NP superstructures have shown a wide range of promise for applications in electronic and photonic devices, such as field‐effect transistors, magnetoresistive components, optical information recording, and solar cells.
Self‐assembly of inorganic nanoparticles into functional superstructures have attracted a lot of attention recently. The combination of inorganic nanoparticles and polymers or DNA gives rise to various applications, for example, photonic storage material. This review summarizes the latest progress in terms of design and application of inorganic nanoparticle superstructures and proposes its future challenges.
Core–shell upconversion nanoparticle@metal–organic framework (UCNP@MOF) nanostructures are constructed by coating hexagonal NaYF4:Yb,Er nanoparticle (NP) cores with amino‐functionalized iron ...carboxylate MOF shells. These nanostructures combine the near‐infrared optical property of the UCNP cores and the T2‐magnetic response (MR) imaging property of the MOF shells. After surface modification, the core–shell nanostructures are demonstrated as high‐resolution nanoprobes for targeted luminescence/MR imaging both in vitro and in vivo.
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