The nature of metal-organic frameworks(MOFs) allows the implementation of desired properties by filling the framework cavities with various guest molecules and clusters molecule.1 Encapsulation of metal nanoparticles ...
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The nature of metal-organic frameworks(MOFs) allows the implementation of desired properties by filling the framework cavities with various guest molecules and clusters molecule.1 Encapsulation of metal nanoparticles in MOFs(MNPs@MOFs) is interesting in many applications especially for gas adsorption/separation and heterogeneous catalyst applications of MOFs. There are several reports regarding metal nanoparticles such as Cu, Ru, Au, Pt and Pd etc. loaded in MOFs.2 Palladium(Pd) is one of the metal which have been used for variety of catalytic reaction e.g. hydrogenation, oxidation, homo-cross coupling etc.3 Till now, different strategies are used to prepare nano-Pd@MOFs, in which the MOF provide a confined space for nucleation of metal nanoparticles as host materials, including chemical vapor deposition, solution infiltration, and solid grinding etc. Here, we report a new approach to encapsulate Pd-nanoparticle instantaneously into ZIF-8 by spray-drying. The XRD was used to evaluate the crystal structure and proved that the spry dried nano-Pd@ZIF-8 did not bare Pd crystals. The HR-TEM images showed that the sizes of the encapsulated Pd nanopaticles were in the range of 2-10 nm. The bright-field and dark-field TEM images demonstrate that most of the nano-Pd particles are dispersed and encapsulated in ZIF-8 cages. This concept demonstrates that the spray-drying technique possess great potential for simultaneous encapsulation of nanoparticles in MOFs(MNPs@MOFs) and also for applications in catalytic reaction.
A novel nerve repairing material PRGD/PDLLA/β-TCP was synthesized and characterized with Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and mass loss ratio. The effects of PDLLA o...
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Sheet-like Cu-ZnS heterostructured composites were prepared by the combination of microwave hydrothermal and cation exchange methods, according to the interfacial charge transfer theory. The fabrication of the heteroj...
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We apply our symmetry based Power tensor technique to test conformity of PLANCK Polarization maps with statistical isotropy. On a wide range of angular scales (l = 40 − 150), our preliminary analysis detects many stat...
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By using solution combustion synthesis method, several Li-Co delafossite catalysts were prepared via a highly exothermic and self-sustaining reaction. The prepared catalysts were characterized by XRD, SEM and the cata...
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By using solution combustion synthesis method, several Li-Co delafossite catalysts were prepared via a highly exothermic and self-sustaining reaction. The prepared catalysts were characterized by XRD, SEM and the catalytic activities of the catalysts were evaluated by small sample experiment. It is shown that under loose contact conditions this catalyst can catalyze soot combustion at 360 ℃, and the best prepared catalyst Li Co0.9O2 can ignite soot combustion below 300 ℃. In the incompletely synthesized catalysts the Co cations shift to higher electrovalence, so the number of the surface adsorbed oxygen（O-） of the prepared delafossite catalysts increase and Li Co0.9O2 has the optimum catalytic activity.
Iridium dioxide with different morphologies(nanorod and nanogranular) is successfully prepared by a modified sol-gel and Adams methods. The catalytic activity of both samples for oxygen reduction reaction is investiga...
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Iridium dioxide with different morphologies(nanorod and nanogranular) is successfully prepared by a modified sol-gel and Adams methods. The catalytic activity of both samples for oxygen reduction reaction is investigated in an alkaline solution. The electrochemical results show that the catalytic activity of the nanogranular Ir O2 sample is superior to that of the nanorod sample due to its higher onset potential for oxygen reduction reaction and higher electrode current density in low potential region. The results of Koutecky-Levich analysis indicate that the oxygen reduction reaction catalyzed by both samples is a mixture transfer pathway. It is dominated by four electron transfer pathway for both samples in high overpotential area, while it is controlled by two electron transfer process for both samples in low overpotential area.
In this paper, polyurethane （PU） materials with different contents of hard segment （20%, 25%, 30%） were prepared based on hexamethylene diisocyanate and polycarbonate diols by solution polymerization. The obtained...
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In this paper, polyurethane （PU） materials with different contents of hard segment （20%, 25%, 30%） were prepared based on hexamethylene diisocyanate and polycarbonate diols by solution polymerization. The obtained polycarbonate-urethane （PCU） elastomers were characterized by very good hydrophobic property and excellent resistance to hydrolysis. Hemolysis, recalification time and platelet-rich plasma adhesion were used to evaluate the blood compatibility of the materials. L929 cells cultured with leach liquor of these PU membranes were selected to perform the cytotoxicity experiments. The results indicate that the hemolysis rates of PU membranes are all less than 5%, which can meet the requirement of the national standards for biomaterials. However, compared with 20% and 30% groups, the recalification time of the sample containing 25% hard segment is longer, while the number of platelet adhesion is less. Additionally, cells cultured in the leach liquor of PU membranes with 25% hard segment proliferated relatively more thriving, meaning that this proportion of the material has the lowest cytotoxicity.
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