The gradient-structure is ideal nanostructure for conversion-type anodes with drastic volume change. Here, we demonstrate an inorganic-organic competitive coating strategy for constructing ...gradient-structured ferroferric oxide-carbon nanospheres, in which the deposition of ferroferric oxide nanoparticles and polymerization of carbonaceous species are competitive and well controlled by the reaction thermodynamics. The synthesized gradient-structure with a uniform size of ~420 nm consists of the ferroferric oxide nanoparticles (4-8 nm) in carbon matrix, which are aggregated into the inner layer (~15 nm) with high-to-low component distribution from inside to out, and an amorphous carbon layer (~20 nm). As an anode material, the volume change of the gradient-structured ferroferric oxide-carbon nanospheres can be limited to ~22% with ~7% radial expansion, thus resulting in stable reversible specific capacities of ~750 mAh g
after ultra-long cycling of 10,000 cycles under ultra-fast rate of 10 A g
. This unique inorganic-organic competitive coating strategy bring inspiration for nanostructure design of functional materials in energy storage.
A novel FeCo nanoparticle embedded nanoporous carbon composite (Fe-Co/NPC) was synthesized via in situ carbonization of dehydro-ascorbic acid (DHAA) coated Fe3O4 nanoparticles encapsulated in a ...metal-organic framework (zeolitic imidazolate framework-67, ZIF-67). The molar ratio of Fe/Co significantly depends on the encapsulated content of Fe3O4 in ZIF-67. The composites filled with 50 wt% of the Fe-Co/NPC-2.0 samples in paraffin show a maximum reflection loss (RL) of -21.7 dB at a thickness of 1.2 mm; in addition, a broad absorption bandwidth for RL < -10 dB which covers from 12.2 to 18 GHz can be obtained, and its minimum reflection loss and bandwidth (RL values exceeding -10 dB) are far greater than those of commercial carbonyl iron powder under a very low thickness (1-1.5 mm). This study not only provides a good reference for future preparation of carbon-based lightweight microwave absorbing materials but also broadens the application of such kinds of metal-organic frameworks.
Ultrafine nanoparticles with organic–inorganic hybridization have essential roles in myriad applications. Over the past three decades, although various efforts on the formation of organic or ...inorganic ultrasmall nanoparticles have been made, ultrafine organic–inorganic hybrid nanoparticles have scarcely been achieved. Herein, a family of ultrasmall hybrid nanoparticles with a monodisperse, uniform size is synthesized by a facile thermo‐kinetics‐mediated copolymer monomicelle approach. These thermo‐kinetics‐mediated monomicelles with amphiphilic ABC triblock copolymers are structurally robust due to their solidified polystyrene core, endowing them with ultrahigh thermodynamic stability, which is difficult to achieve using Pluronic surfactant‐based micelles (e.g., F127). This great stability combined with a core–shell–corona structure makes the monodispersed monomicelles a robust template for the precise synthesis of ultrasmall hybrid nanoparticles with a highly uniform size. As a demonstration, the obtained micelles/SiO2 hybrid nanoparticles display ultrafine sizes, excellent uniformity, monodispersity, and tunable structural parameters (diameters: 24–47 nm and thin shell thickness: 2.0–4.0 nm). Notably, this approach is universal for creating a variety of multifunctional ultrasmall hybrid nanostructures, involving organic/organic micelle/polymers (polydopamine) nanoparticles, organic/inorganic micelle/metal oxides (ZnO, TiO2, Fe2O3), micelle/hydroxides (Co(OH)2), micelle/noble metals (Ag), and micelle/TiO2/SiO2 hybrid composites. As a proof of concept, the ultrasmall micelle/SiO2 hybrid nanoparticles demonstrate superior toughness as biomimetic materials.
A library of ultrasmall hybrid nanoparticles with great uniformity, monodispersity, and tunable shell thickness is successfully synthesized by a facile thermo‐kinetics‐mediated copolymer monomicelle approach. This monomicelle with a solidified polystyrene core has ultrahigh thermodynamic stability. Combined with a unique core–shell–corona structure, this monomicelle is a very general template to synthesize various ultrasmall, monodispersed hybrid nanoparticles with excellent uniformity.
Abstract
The manipulation of polymeric micelles across extended-length scales is a key challenge in the design of integrated mesoporous materials with well-defined geometry and advanced functions. ...Herein, we demonstrate a modular assembly strategy to construct metal nanoparticle functionalized mesoporous carbon two-dimensional (2D) nanosheets by organizing zero-dimensional (0D) spherical monomicelle modules on the 2D supporting blocks. The modular assembly process involves two key steps: the “modularization” step is used to synthesize highly uniform metal–catecholamine (MC) complex functionalized monomicelle “modules” that can be conveniently assembled on the 2D supporting blocks (graphene oxide (GO), WS
2
, and MXene) in the following “assembly” step. After an annealing process, the resultant composites possess a single-layered 2D nanosheet surrounded by two single-layered mesoporous carbon at both sides and exhibit highly ordered mesostructures with large surface areas (~385 m
2
g
−1
), tunable pore sizes (16–25 nm) and highly dispersed metal-containing nanoparticles. Due to the modularity of this assembly process, a range of metal species (Co, Fe, Ni, V, Cu, Pd, FeCo, CoNi, and FeCoNi) can be in-situ incorporated into the 2D mesoporous frameworks, which are partially embedded in the pore walls with the remaining part exposed in the pore channels. Benefiting from the unique textual structures, the resultant GO-derived functional mesoporous carbon nanosheets (Co as the functional species and being annealed at 850 °C) exhibit excellent electrocatalytic activity, long-term stability, and superior methanol tolerance for oxygen reduction reaction, which holds great potential as a catalyst for fuel cells.
► The graphene can accept the photoexcited electrons from BiOBr and thus inhibits the electron–hole recombination. ► The graphene significantly improved the photocatalytic activity under visible ...light irradiation. ► The photocatalytic activity of graphene/BiOBr strongly depend on the amount of graphene.
The study presented in this work deals with the synthesis of graphene/BiOBr composite following hydrothermal reaction between graphene oxide and BiOBr. The results achieved demonstrated that the presence of graphene on the surface of BiOBr significantly improved the photocatalytic activity, under visible light irradiation, owing to the low isoelectric characteristics of graphene and better interfacial electron transfer between BiOBr and graphene. The effect of different amounts of graphene such as 1, 3, 6 and 10wt% on the photocatalytic and adsorption efficiency was investigated. Our results showed that there exists an optimum concentration of graphene (∼6wt%) for the best photocatalytic response of BiOBr which could be due to crucial energy dissipation. The photocatalytic and adsorption efficiency of the composites were investigated by studying the removal of Sulforhodamine 640 dye as a probe reaction.
Metal oxide nanocrystals/mesoporous carbon composite materials are promising in the energy storage field. However, the construction of stoichiometric ternary nanocrystals‐functionalized mesoporous ...carbon materials remains a great challenge. Herein, the synthesis of ultradispersed and ultrasmall LiTiO2 nanocrystals/ordered mesoporous carbon composites via a chelation‐mediated multicomponent coassembly strategy is reported. In this case, the self‐assembly into ordered mesostructures and the crystallization of nanoparticle processes can be decoupled by the molecular chelate strategy where citrate ligands can effectively inhibit the hydrolysis and phase separation of metal oxide precursors and confine the crystallization into nanocrystals without aggregation. The obtained 33%‐LiTiO2–OMC composites present a high specific surface area (≈912 m2 g−1), a large pore volume (≈0.62 cm3 g−1), a uniform pore size (≈4.1 nm), and ultradispersed LiTiO2 nanocrystals (≈3 nm). When loading 60% sulfur, the composites exhibit a high reversible capacity (966 mAh g−1 after 100 cycles at 0.5C), an excellent rate capacity (700 mAh g−1 at 5C), and a long‐term cycling performance (63% retention after 1000 cycles at 5C). This method is very simple and reproducible, which paves a new way for the design and synthesis of functional mesoporous materials.
A chelation‐mediated multicomponent coassembly strategy is developed for the controllable synthesis of ultradispersed and ultrasmall LiTiO2 nanocrystals/ordered mesoporous carbon composites with high specific surface areas, large pore volumes, and uniform pore size. When loading 60% sulfur, the composites exhibit a high reversible capacity, an excellent rate capacity, and a long‐term cycling performance.
Manipulating the super-assembly of polymeric building blocks still remains a great challenge due to their thermodynamic instability. Here, we report on a type of three-dimensional hierarchical ...core-satellite SiO
@monomicelle spherical superstructures via a previously unexplored monomicelle interfacial super-assembly route. Notably, in this superstructure, an ultrathin single layer of monomicelle subunits (~18 nm) appears in a typically hexagon-like regular discontinuous distribution (adjacent micelle distance of ~30 nm) on solid spherical interfaces (SiO
), which is difficult to achieve by conventional super-assembled methods. Besides, the number of the monomicelles on colloidal SiO
interfaces can be quantitatively controlled (from 76 to 180). This quantitative control can be precisely manipulated by tuning the interparticle electrostatic interactions (the intermicellar electrostatic repulsion and electrostatic attractions between the monomicelle units and the SiO
substrate). This monomicelle interfacial super-assembly strategy will enable a controllable way for building multiscale hierarchical regular micro- and/or macroscale materials and devices.
Uniform well-crystallized flower-like BiOI nanoplates contained 3.7 nm mesopores, which may be attributed to the internanosheet spaces of BiOI with maximum pore diameters of about 30 nm, were ...successfully synthesized via a simple ethylene glycol-assisted solvothermal method. The as-prepared porous BiOI nanoplates exhibited excellent adsorption ability, and the saturated extent of adsorption of BiOI over an RhB solution was as high as 197 mg/g, which is much higher than those for BiOCl and BiOBr prepared via the same method and with a similar surface area. The probable adsorption mechanism could have originated from the interaction between the I atom in BiOI and a proton in RhB at different pH values and temperatures. With visible light irradiation (
λ
> 420 nm), 80 % of the RhB was degraded in 4 h, while BiOI still demonstrated reasonably outstanding photocatalytic ability under green light (
λ
= 550 ± 15 nm) because of its low-energy gap (1.72 eV). The degradation test for BiOI under irradiation at
λ
= 550 ± 15 nm is an excellent achievement for field applications because the catalyst can be applied in solar irradiation to remove organic pollutants, which may be of great value BiOI complex.
Functional mesoporous carbons have attracted significant scientific and technological interest owning to their fascinating and excellent properties. However, controlled synthesis of functional ...mesoporous carbons with large tunable pore sizes, small particle size, well-designed functionalities, and uniform morphology is still a great challenge. Herein, we report a versatile nanoemulsion assembly approach to prepare N-doped mesoporous carbon nanospheres with high uniformity and large tunable pore sizes (5–37 nm). We show that the organic molecules (e.g., 1,3,5-trimethylbenzene, TMB) not only play an important role in the evolution of pore sizes but also significantly affect the interfacial interaction between soft templates and carbon precursors. As a result, a well-defined Pluronic F127/TMB/dopamine nanoemulsion can be facilely obtained in the ethanol/water system, which directs the polymerization of dopamine into highly uniform polymer nanospheres and their derived N-doped carbon nanospheres with diversely novel structures such as smooth, golf ball, multichambered, and dendritic nanospheres. The resultant uniform dendritic mesoporous carbon nanospheres show an ultralarge pore size (∼37 nm), small particle size (∼128 nm), high surface area (∼635 m2 g–1), and abundant N content (∼6.8 wt %), which deliver high current density and excellent durability toward oxygen reduction reaction in alkaline solution.
Nanostructured carbon materials with hollow structures derived from metal organic frameworks (MOFs) have attracted considerable attention due to their low density for microwave absorption. However, ...their poor impedance matching worsens the absorption properties. The rational design and fabrication of complex hollow nanocarbon materials with excellent impedance matching still remains a challenge. Herein, we report a simple strategy to fabricate porous CuO/carbon composites by nitrate impregnation into a MOF template (thermal decomposition of zeolitic imidazolate frameworks, ZIF-67). When used as microwave absorbing materials, these hollow CuO/carbon composite polyhedra exhibited excellent impedance matching, light weight and strong absorption. An optimal reflection loss (RL) of −57.5 dB is achieved at 14.9 GHz with a matching thickness of 1.55 mm and RL values less than −10 dB can be gained in the range of 13-17.7 GHz. The best absorbing performance of the composites mainly originates from the high loss of the porous carbon obtained by the carbonization of ZIF-67, and the improvement of the impedance matching with the embedding of CuO. This work may provide a general way for fabricating porous metal oxides/carbon composites for lightweight microwave absorbing materials.
A simple strategy to fabricate porous CuO/carbon composites by nitrate impregnation into a MOF template is reported in this study. The obtained CuO/carbon samples show improved impedance matching and excellent microwave absorbing properties.
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