• Reece Cherry opublikował 1 rok, 3 miesiące temu

    Based on these results, the reaction mechanism for toluene oxidation over the OMS-2 based catalyst is proposed. It is expected to provide an effective preparation method to obtain high-performance catalysts for the VOCs oxidation at low temperatures.Polyolefin (PO) cables used in confined spaces need to have low smoke, low heat release, low toxic gas release and excellent physical properties. In this work, a series of rare earth stannates Re2Sn2O7 (RES, Re = Nd, Sm, Gd) with high temperature catalytic performance were prepared by hydrothermal method for synergistic flame retardant PO/IFR. The flame retardancy, heat release, smoke density, toxic gas release and physical properties of PO composites were thoroughly studied in detail. The RES could enhance the vertical burning rating and the limiting oxygen index (LOI) of PO/IFR composites. Moreover, the residual char of the thermogravimetric analysis increased from 9.7% to 11.4 wt% after the RES added in PO/IFR system. Interestingly, the PO/IFR system containing Gd2Sn2O7 exhibits the lowest peak heat release rate of 233.7 kW/m2. Excellent flame resistance due to the formation of a complete and compact protective char layer. In addition, the toxic release of PO during combustion is also effectively reduced by introducing the RES. The tube furnace combustion test shows that the emission of carbon oxide (CO) and hydrogen cyanide (HCN) of PO/IFR/Gd2Sn2O7 are the lowest. It can be attributed to the catalytic effect of rare earth elements and the blocking effect of the dense char layer. In addition, compared with the PO/IFR composites, the PO/IFR/RES system demonstrate higher mechanical properties and volume resistivity. Therefore, the addition of RES has a positive effect on improving the physical properties and fire safety properties of the PO/IFR cable composites, especially suitable for using in confined spaces.In this work, a two-dimensional heterostructure of molybdenum disulfide (MoS2) and nickelhydroxyloxide (NiOOH) nanosheets supported on catkin-derived mesoporous carbon (C-MC) was constructed and exploited as an efficient electrocatalyst for overall water splitting. The C-MC nanostructure was prepared by pyrolyzing biomass material of catkin at 600 °C in N2 atmosphere. The C-MC network exhibited hollow nanotube structure and had a large specific surface area, comprising trace nitrogen and a large amount of oxygen vacancies. It further served as the support for the growth of NiOOH nanosheets (NiOOH@C-MC), which was combined with MoS2 nanosheets by in situ growth, yielding a multicomponent electrocatalyst (MoS2@NiOOH@C-MC). By integrating the superior hydrogen evolution reaction (HER) performance of MoS2, oxygen evolution reaction (OER) performance of NiOOH, and the fast electron transfer capability of C-MC, the prepared MoS2@NiOOH@C-MC illustrated a low potential of – 250 mV for HER and 1.51 V for OER at the current density of 10 mV cm-2. Consequently, when applied as the working electrode for driving overall water splitting in a two-electrode system, the bifunctional MoS2@NiOOH@C-MC electrocatalyst displayed a low cell voltage of 1.62 V at the current density of 10 mA cm-2. The present work provides a new strategy that uses biomass material for developing bifunctional electrocatalyst for overall water splitting.Compressibility of zinc-manganese oxide (Zn-MnO2) batteries is an essential element of modern flexible electronics. Hydrogel electrolytes with superior elasticity and compressibility are highly demand to guarantee a stable energy output of the flexible Zn-MnO2 battery. Herein, a highly compressible hydrogel electrolyte was developed by introducing soybean protein isolate nanoparticles (SPI) into covalently cross-linked polyacrylamide (PAAM) polymer networks. The SPI/PAAM hydrogel electrolyte for Zn-MnO2 battery possessed outstanding reversible compressibility due to the aggregation of SPI nanoparticles on the PAAM chains through the weak electrostatic interaction, which could dissipate energy effectively. Consequently, the Zn-MnO2 battery based on the compressible hydrogel electrolyte displayed a decent specific capacity (299.3 mA h g-1) and desirable capacity retention rate (78.2%) after 500 charge/discharge cycles. Notably, the device could maintain stable power output under 96% compress strain and light the bulb even under severe mechanical stimulation like being-bent and hammered. It’s believed that the compressible Zn-MnO2 batteries hold enormous potential as the energy storage devices in the field of flexible wearable electronics.We describe the antithrombotic properties of nanopatterned coatings created by self-assembly of poly(styrene-block-2-vinylpyridine) (PS-b-P2VP) with different molecular weights. By changing the assembly conditions, we obtained nanopatterns that differ by their morphology (size and shape of the nanopattern) and chemistry. The surface exposition of P2VP block allowed quaternization, i.e. introduction of positive surface charge and following electrostatic deposition of heparin. Proteins (albumin and fibrinogen) adsorption, platelet adhesion and activation, cytocompatibility, and reendothelization capacity of the coatings were assessed and discussed in a function of the nanopattern morphology and chemistry. We found that quaternization results in excellent antithrombotic and hemocompatible properties comparable to heparinization by hampering the fibrinogen adhesion and platelet activation. In the case of quaternization, this effect depends on the size of the polymer blocks, while all heparinized patterns had similar performance showing that heparin surface coverage of 40 % is enough to improve substantially the hemocompatibility.

    The stability of fluid-fluid interface is key to control the displacement efficiency in multiphase flow. The existence of particles can alter the interfacial dynamics and induce various morphological patterns. Moreover, the particle aggregations are expected to have a significant impact on the interface stability and patterns.

    Monodisperse polyethylene particles of different sizes are uniformly mixed in silicone oil to form the granular mixtures, which are injected into a transparent radial Hele-Shaw cell through different strategies to obtain the homogeneous and inhomogeneous (with particle aggregations) initial states. Subsequently, a systematic study of morphology and interface stability during the withdrawal of granular mixtures is performed.

    For homogeneous mixtures, we observe earlier onset of fingering, more fingers and lower gas saturation at breakthrough than for pure fluid with equivalent viscosity. This effect can be attributed to the particle-induced perturbations. For inhomogeneous mixturespplications.Elucidation of reaction mechanisms in forming nanostructures is relevant to obtain robust and affordable protocols that can lead to materials with enhanced properties and good reproducibility. Here, the formation of magnetic iron oxide monocrystalline nanoflowers in polyol solvents using N-methyldiethanolamine (NMDEA) as co-solvent has been shown to occur through a non-classical crystallization pathway. This pathway involves intermediate mesocrystals that, in addition, can be transformed into large single colloidal nanocrystals. Interestingly, the crossover of a non-classical crystallization pathway to a classical crystallization pathway can be induced by merely changing the NMDEA concentration. The key is the stability of a green rust-like intermediate complex that modulates the nucleation rate and growth of magnetite nanocrystals. The crossover separates two crystallization domains (classical and non-classical) and three basic configurations (mesocrystals, large and small colloidal nanocrystals). The above finding facilitated the synthesis of magnetic materials with different configurations to suit various engineering applications. Consequently, the effect of the single and multicore configurations of magnetic iron oxide on the biomedical (magnetic hyperthermia and enzyme immobilization) and catalytic activity (Fenton-like reactions and photo-Fenton-like processes driven by visible light irradiation) has been experimentally demonstrated.Constructing interpenetrating heterointerface with reasonable interface energy barriers to improve electron/ion transport and accelerate the deposition/decomposition of lithium sulfide (Li2S) is an effective method to improve the electrochemical performance of lithium-sulfur (Li-S) batteries. Herein, NiCoO2/NiCoP heterostructures with hollow nanocage morphology are prepared for efficient multifunctional Li-S batteries. The hollow nanocage structure exposes abundant active sites, traps lithium polysulfides and inhibits the shuttle effect. The NiCoO2/NiCoP heterostructure, combing strong adsorption capacity of NiCoO2 and excellent catalytic ability of NiCoP, facilitates the process of anchoring-diffusion-transformation of polysulfides. The successful construction of heterostructures reduces the reaction barrier, accelerating the lithium ion (Li+) diffusion rate and thus effectively enhancing the redox reaction kinetics. More importantly, NiCoO2/NiCoP heterostructure plays a role in self-cleaning that minimizes solid sulfur species accumulation to maintain surface clean during long cycling for a continuously catalysis of the polysulfides conversion reactions. With the merit of these features, the NiCoO2/NiCoP modified separator exhibits excellent cycling stability with a low capacity decay of 0.043% per cycle up to 1000 cycles at 2 C. The design of NiCoO2/NiCoP hollow nanocage heterostructures offers a new option for high-performance electrochemical energy storage devices.Recent progress in photocatalytic hydrogen generation reaction highlights the critical role of co-catalysts in enhancing the solar-to-fuel conversion efficiency of diverse band-matched semiconductors. Because of the compositional flexibility, adjustable microstructure, tunable crystal phase and facet, cobalt-based co-catalysts have stimulated tremendous attention as they have high potential to promote hydrogen evolution reaction. However, a comprehensive review that specifically focuses on these promising materials has not been reported so far. Therefore, this present review emphasizes the recent progress in the pursuing of highly efficient Co-based co-catalysts for water splitting, and the advances in such materials are summarized through the analysis of structure-activity relationships. The fundamental principles of photocatalytic hydrogen production are profoundly outlined, followed by an elaborate discussion on the crucial parameters influencingthe reaction kinetics. Then, the co-catalytic reactivities of various Co-based materials involving Co, Co oxides, Co hydroxides, Co sulfides, Co phosphides and Co molecular complexes, etc, are thoroughly discussed when they are coupled with host semiconductors, with an insight towards the ultimateobjective of achieving a rationally designed photocatalyst for enhancing water splitting reaction dynamics. Finally, the current challenge and future perspective of Co-based co-catalysts as the promising noble-metal alternative materials for solar hydrogen generation are proposed and discussed.

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