The integration of metal/metal oxide nanoparticles (NPs) into metal–organic frameworks (MOFs) to form composite materials has attracted great interest due to the broad range of applications. However, ...to date, it has not been possible to encapsulate metastable NPs with high catalytic activity into MOFs, due to their instability during the preparation process. For the first time, we have successfully developed a template protection–sacrifice (TPS) method to encapsulate metastable NPs such as Cu2O into MOFs. SiO2 was used as both a protective shell for Cu2O nanocubes and a sacrificial template for forming a yolk–shell structure. The obtained Cu2O@ZIF‐8 composite exhibits excellent cycle stability in the catalytic hydrogenation of 4‐nitrophenol with high activity. This is the first report of a Cu2O@MOF‐type composite material. The TPS method provides an efficient strategy for encapsulating unstable active metal/metal oxide NPs into MOFs or maybe other porous materials.
Three birds with one stone: A template protection–sacrifice method was developed to encapsulate metastable metal/metal oxide nanoparticles such as Cu2O into metal–organic frameworks. SiO2 serves as a sacrificial template for forming the yolk–shell structure, as a protective shell for Cu2O nanocubes, and as a space holder in the porous composite.
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In the surroundings of carbon neutrality, nano‐Cu2O is considered a promising catalyst for the electrochemical CO2 reduction reaction (ECO2RR), whose improvements in product selectivity still require ...considerable efforts. Here, we present an efficient strategy for controlling the ECO2RR product by modifying the surface of nano‐Cu2O, i.e., by controlling the exposed facets via a reductant‐controlled method to achieve the highest C2H4 selectivity (Faradic efficiency=74.1 %) for Cu2O‐based catalysts in neutral electrolytes, and introducing a well‐suited metal–organic framework (MOF) coating on the surface of nano‐Cu2O to obtain syngas completely with an appropriate H2:CO ratio. Detailed mechanism and key intermediate have been illustrated by DFT calculations. Our systematic strategy is expected to control the ECO2RR product, improve the selectivity, and provide a reliable method for CO2 management and the green production of important carbon resources.
Electrochemical CO2 reduction reaction (ECO2RR) with controllable production of important carbon resources was achieved by a surface modification strategy of nano‐Cu2O catalysts. Through facet controlling the highest C2H4 selectivity among Cu2O‐based catalysts was achieved, while the products were completely converted to syngas with an appropriate H2:CO ratio via a MOF coating on the surface of the nano‐Cu2O.
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Metal–organic frameworks (MOFs) are constructed by periodically alternate metal ions with organic ligands, which offer structural diversity and a wide range of interesting properties as an attractive ...classification of crystalline porous materials. Integration of MOFs with other size‐limited functional centers can supply new multifunctional composites, which exhibit both the properties of the components and new characteristics due to the combination of MOFs with the selected loadings. In recent years, integration of metal/metal oxide nanoparticles (MNPs) into MOFs to form the composite catalysts has attracted considerable attention due to the superior performance. In this review, the latest studies and up‐to‐date developments on the design and synthetic strategy of new MNP@MOF composite catalysts are specifically highlighted. Both the achievements and problems are evaluated and proposed, and the opportunities and challenges of MNP@MOF composite catalysts are discussed.
The incorporation of metal and/or metal oxide nanoparticles (MNPs) into metal–organic frameworks (MOFs) to form composite catalysts has received increasing attention because of their excellent catalytic performance compared to the corresponding individual components. In this review, the latest research and recent developments in the design and synthesis strategies of MNP@MOF composite catalysts are highlighted.
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Metal-organic frameworks (MOFs) have risen as a kind of porous materials that are constructed by the coordination of organic ligands to metal centers or clusters, providing compelling potential for ...various fields of research. In this frontier article, we demonstrate the recent developments in MOF-based materials for electrochemical sensing applications, and the current challenges and some prospects in this field are also discussed.
A summary of the most recent advancements of metal-organic frameworks (MOFs) for electrochemical sensing is listed in this frontier article.
Higher-order genome organization and its variation in different cellular conditions remain poorly understood. Recent high-coverage genome-wide chromatin interaction mapping using Hi-C has revealed ...spatial segregation of chromosomes in the human genome into distinct subcompartments. However, subcompartment annotation, which requires Hi-C data with high sequencing coverage, is currently only available in the GM12878 cell line, making it impractical to compare subcompartment patterns across cell types. Here we develop a computational approach, SNIPER (Subcompartment iNference using Imputed Probabilistic ExpRessions), based on denoising autoencoder and multilayer perceptron classifier to infer subcompartments using typical Hi-C datasets with moderate coverage. SNIPER accurately reveals subcompartments using moderate coverage Hi-C datasets and outperforms an existing method that uses epigenomic features in GM12878. We apply SNIPER to eight additional cell lines and find that chromosomal regions with conserved and cell-type specific subcompartment annotations have different patterns of functional genomic features. SNIPER enables the identification of subcompartments without high-coverage Hi-C data and provides insights into the function and mechanisms of spatial genome organization variation across cell types.
The safety of energy storage equipment has always been a stumbling block to the development of battery, and sodium ion battery is no exception. However, as an ultimate solution, the use of ...non‐flammable electrolyte is susceptible to the side effects, and its poor compatibility with electrode, causing failure of batteries. Here, we report a non‐flammable electrolyte design to achieve high‐performance sodium ion battery, which resolves the dilemma via regulating the solvation structure of electrolyte by hydrogen bonds and optimizing the electrode–electrolyte interphase. The reported non‐flammable electrolyte allows stable charge‐discharge cycling of both sodium vanadium phosphate@hard carbon and Prussian blue@hard carbon full pouch cell for more than 120 cycles with a capacity retention of >85 % and high cycling Coulombic efficiency (99.7 %).
Safety is always a topic of concern after reports of devices catching fire due to battery failure. Using non‐flammable electrolyte as an ultimate solution is difficult to be applied to commercial batteries because of various problems such as poor compatibility, high viscosity and so on. Here, we report a non‐flammable electrolyte with excellent comprehensive performance, and applied it to sodium‐ion pouch cells with different promising materials.
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7.
Biodegradable materials for bone defect repair Wei, Shuai; Ma, Jian-Xiong; Xu, Lai ...
Military Medical Research/Military medical research,
11/2020, Volume:
7, Issue:
1
Journal Article
Peer reviewed
Open access
Compared with non-degradable materials, biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects, and have attracted extensive attention from ...researchers. In the treatment of bone defects, scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role, which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue. Traditional biodegradable materials include polymers, ceramics and metals, which have been used in bone defect repairing for many years. Although these materials have more or fewer shortcomings, they are still the cornerstone of our development of a new generation of degradable materials. With the rapid development of modern science and technology, in the twenty-first century, more and more kinds of new biodegradable materials emerge in endlessly, such as new intelligent micro-nano materials and cell-based products. At the same time, there are many new fabrication technologies of improving biodegradable materials, such as modular fabrication, 3D and 4D printing, interface reinforcement and nanotechnology. This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing, especially the newly emerging materials and their fabrication technology in recent years, and look forward to the future research direction, hoping to provide researchers in the field with some inspiration and reference.
Silver nanoparticles were successfully supported on the zeolite‐type metal–organic framework MIL‐101 to yield Ag@MIL‐101 by a simple liquid impregnation method. For the first time, the conversion of ...terminal alkynes into propiolic acids with CO2 was achieved by the use of the Ag@MIL‐101 catalysts. Owing to the excellent catalytic activity, the reaction proceeded at atmospheric pressure and low temperature (50 °C). The Ag@MIL‐101 porous material is of outstanding bifunctional character as it is capable of simultaneously capturing and converting CO2 with low energy consumption and can be recovered easily by centrifugation.
Silver nanoparticles were supported on the zeolite‐type metal–organic framework MIL‐101 by a simple liquid impregnation method to yield Ag@MIL‐101. CO2 and terminal alkynes could be converted into propiolic acids in the presence of the very active Ag@MIL‐101 catalyst at atmospheric pressure and low temperature (50 °C).
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Covalent organic frameworks (COFs) have wide‐ranging applications, and their host–guest interactions play an essential role in the achievement of COF functions. To investigate these host–guest ...interactions, it is necessary to locate all atoms, especially hydrogen atoms. However, it is difficult to determine the hydrogen atomic positions in COFs because of the complexities in synthesizing high‐quality large single crystals. Three‐dimensional electron diffraction (3D ED) has unique advantages for the structural determination of nanocrystals and identification of light atoms. In this study, it was demonstrated for the first time that the hydrogen atoms of a COF, not only on the framework but also on the guest molecule, can be located by 3D ED using continuous precession electron diffraction tomography (cPEDT) under cryogenic conditions. The host–guest interactions were clarified with the location of the hydrogen atoms. These findings provide novel insights into the investigation of COFs.
The hydrogen atoms of a covalent organic framework on the framework and guest molecules were located using cryo‐3D electron diffraction for the first time. The host–guest interactions in the framework material were clarified by locating the hydrogen atoms.
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Arsenic, cadmium, lead, and mercury are toxic elements that are almost ubiquitously present at low levels in the environment because of anthropogenic influences. Dietary intake of plant-derived food ...represents a major fraction of potentially health-threatening human exposure, especially to arsenic and cadmium. In the interest of better food safety, it is important to reduce toxic element accumulation in crops. A molecular understanding of the pathways responsible for this accumulation can enable the development of crop varieties with strongly reduced concentrations of toxic elements in their edible parts. Such understanding is rapidly progressing for arsenic and cadmium but is in its infancy for lead and mercury. Basic discoveries have been made in
Arabidopsis
, rice, and other models, and most advances in crops have been made in rice. Proteins mediating the uptake of arsenic and cadmium have been identified, and the speciation and biotransformations of arsenic are now understood. Factors controlling the efficiency of root-to-shoot translocation and the partitioning of toxic elements through the rice node have also been identified.
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