查看更多>>摘要：? 2021There is a large amount of energy used in everyday life. Whether it is inside a residence, transportation, or even the production process of consumer goods, these activities require a tremendous energy amount. Currently, there is a need for more energy. Lithium-ion batteries are of particular interest due to their small size, low weight, high electrical Capacity, safety, and long life. Carbonaceous anode materials are commonly utilized in energy storage systems. This study synthesized mesoporous carbon powder from bee-collected pollens through carbonization and KOH activation as an anode in lithium-ion batteries. An X-ray diffractometer (XRD) was used to characterize phase formation. Raman Spectrometer analyzed the relation between the strain components and the change of the Raman peak's wavenumber. Also, a Scanning electron microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) were used to characterize the microstructure and chemical composition. In addition, the electrical properties of the sample were also tested. These outstanding results open new paths towards the development of novel Li-ion batteries.
查看更多>>摘要：? 2021 Elsevier Inc.Metal-organic frameworks (MOFs), specially, MIL-101(Cr) are utilized as a catalyst in plenty of industrial catalyst applications. In this study synthesis and characterization of MIL-101(Cr)-ED-Glu-Pd is reported. First, MIL-101(Cr) was functionalized with ethylenediamine (ED) by the post-synthesis method (PSM), second, palladium nanoparticles were entangled on the surface of MIL-101(Cr) with a novel strategy. The morphology and structure of the synthesized MIL-101(Cr)-ED-Glu-Pd were determined by using of XRD (X‐ray diffraction), FT‐IR (Fourier transform infrared), SEM (Scanning electron microscopy), EDX (Energy dispersive analysis of X‐ray), BET (Brunauer Emmett Teller), XPS (X-ray photoelectron spectroscopy), TGA (Thermogravimetric) and ICP‐MS (Inductively coupled plasma mass spectrometry). We surveyed the action of catalytic of MIL-101(Cr)-ED-Glu-Pd in Suzuki?Miyaura connector reaction between phenylboronic acid with aryl halides (Ar‐X, X = I, Br, Cl, F). Our studies show that this compound can be a suitable catalyst in carbon?carbon cross-coupling reactions because of having some advantages such as short time, high yield, and easy reusability.
查看更多>>摘要：? 2021 Elsevier Inc.A set of dendrimeric silica (DS) reinforced polyethylene-based nanocomposites is prepared using a novel and straightforward in-situ catalyst supporting procedure by means of “in-situ” polymerization technique, labeled DS-SA. These materials are characterized with regard to molar masses, filler dispersion, thermal stability, crystalline characteristics, thermal properties and mechanical response and then compared with an equivalent set of samples prepared using a more common method, named DS-MAO, as well as a non-reinforced HDPE reference. The mechanical performance of all these materials is discussed based on the crystalline features and molar masses of the polymeric component together with the dispersion of the DS nanofiller. The results of this study confirm the potential of the DS-SA approach as an innovative and promising technique, with resulting materials achieving superior filler dispersion and significantly higher mechanical performance compared to their DS-MAO analogues at high filler loadings, while retaining the limit stretching ability of HDPE.
查看更多>>摘要：? 2021 Elsevier Inc.In this paper, large-sized covalent organic framework (COF) aerogels were prepared using high-efficiency catalysis under room temperature combined with rapid gel and freeze-drying methods for the first time. Two kinds of COF aerogels with rigid and semi-rigid building blocks were prepared using this method, having good mechanical strength (126 and 106 kPa), elasticity (aerogels structure remains intact after 10 cycles), thermal insulation properties (low thermal conductivity of 0.03 wm?1K?1), low dielectric constant (1 kHz of 1.21 and 1.51), thermal stability and solvent stability, and ultra-light characteristics (densities of 0.029 and 0.040 g cm?3). Compared to the traditional COF methods that generally result in small particles, the high-efficiency catalysis method developed in this paper can be used to prepare large-sized COF aerogels under mild reaction temperatures and within less time conducive to industrial production. This method is expected to greatly broaden the application field and application scope of COF materials.
查看更多>>摘要：? 2021 Elsevier Inc.Carbon dots (CDs) was synthesized by hydrothermal method using o-phenylenediamine. The fluorescence property can be used for metal ion sensing, but the solid-state aggregation caused quenching (ACQ) is the troublesome problem to develop the potential applications of carbon dots. Here, the metal-organic framework (MOF) as a host is not only used for restraining the ACQ effect of CDs but also can be constructed by the dual-emitting system (CDs@ZIF-8). Furthermore, CDs@ZIF-8 with dual-emitting centers can be utilized for detecting copper ions as a ratio fluorescence sensor. The CDs@ZIF-8 fluorescence sensor shows excellent sensitivity, selectivity and strong environmental suitability for sensing Cu2+ ion with the limit of detection (LOD) for Cu2+ ion is 11.712 μM. The CDs@ZIF-8 fluorescent probe was successfully applied to detect Cu2+ ions in an aqueous solution. CDs@ZIF-8 shows a new possibility to fabricate fluorescent molecular probes for the determination of heavy metal ions, which is taken on anti-inference in pH, anion and other influence factors.
查看更多>>摘要：? 2021Pervaporation has shown great promise in recovering alcohol from fermentation broth. However, the separation performance determined by membrane material and structure should be further improved. In this study, polyhedral oligomeric silsesquioxane (POSS) nanocage was used as nanofillers to provide preferential pathways for ethanol molecules in polydimethylsiloxane (PDMS) membrane. To improve dispersion of POSS nanocages in PDMS matrix, the POSS were anchored on the graphene oxide (GO) nanosheets. At the meantime, the aggregation of GO nanosheets could also be prevented as the GO surface turned to be hydrophobic by the modification of POSS, and the nanoporous POSS cage could reduce interface defects between GO nanosheets and PDMS matrix. The obtained POSS-GO/PDMS nanocomposite membranes exhibited excellent separation performance for ethanol permselectivity. The flux could reach 1346.9 g m?2 h?1 with a separation factor of 11.2 when recovery of ethanol from 5 wt% ethanol/water mixture. In addition, the separation performance of the POSS-GO/PDMS membrane could maintain stability in 120 h. Therefore, the POSS modified GO nanosheets shown great potential in the fabrication of ethanol permselective pervaporation membranes.
查看更多>>摘要：? 2021 Elsevier Inc.Furfural contamination of water is a serious problem in the world. The review article highlights on furfural ecotoxicology and the associated molecular mechanisms involved in its toxicity, efficacy of novel adsorbents for the removal of furfural from polluted water, adsorption capacities of adsorbents under different conditions, such as surface area, concentration, adsorption capacity, pH, time, temperature, applicable isotherm models, characterization and percentage removal of furfural. It was showed from the review that CTAB-bentonite is the best adsorbents for the removal of furfural (qmax = 538 mg/g) from aqueous media.A wide range of values for the thermodynamic parameters (both negative and positive) were reported for furfural across different studies. Furfural uptake best-fit both for the Langmuir and Freundlich isotherm models as well as a pseudo second order kinetic model. Additionally, the review also highlighted the molecular modelling and simulations of furfural adsorptions and detail about its future prospects. Among the different treatment options, advanced oxidation processes (AOPs) are likely promising for efficient degradation of furfural in water and wastewater.
查看更多>>摘要：? 2021 Elsevier Inc.As a simple but effective approach to engineer the simultaneous geometric structure and composition diversity into one nano-material, hybrids have geared great research attention, recently. Here, a N-decorated sheet-on-rod heterostructure with hierarchical porosity, as well as homogeneously dispersed Co5.47N, Co0.7Fe0.3, and Fe/Co-Nx species on the phase interface, was developed via pyrolysis of a CMP-on-MOF bimetal hybrid, to achieve the bifunctional oxygen electrocatalytic activity. Conjugated microporous polymers (CMPs) are an emerging class of multifunctional materials combining the features of conventional conjugated polymers and porous materials, simultaneously. CMP-on-MOF was prepared via the assembly of Co-phthalocyanine-CMP (Co-CMP) on the surface of Fe-MIL-88B (Fe-MOF) through a solid-phase synthesis method. The optimized catalyst (PM-900), namely the product of hybrid pyrolysis, is obtained by finely regulating the composition of hybrid (mCMP to mMOF of 1:1) and pyrolysis temperature (900 °C) on the hybrid, simultaneously. The abundant Co5.47N, Co0.7Fe0.3, and atomically dispersed Fe/Co-Nx species are highly catalytically active, and the hierarchical porous structure provides easily accessible pathway for active sites, and the sheet-on-rod structure ensures a high electrical conductivity which is conducive for the catalysis. As a result, the optimum electrocatalyst, denoted as PM-900, presents a superb bifunctional electrocatalytic activity for both the oxygen reduction (ORR) and oxygen evolution reaction (OER) under alkaline conditions. Additionally, a home-made Zn–air battery (ZAB) comprising PM-900 catalyst presents prominent charge-discharge property even outperforms the mixture of Pt/C (20 wt%) and IrO2. The hybrid strategy paves a new avenue for the rational design and synthesis of advanced bifunctional catalysts with intricate and unprecedented porous superstructures for reversible energy storage and conversion applications.
Floriano da Silva J.Deise da Silva Ferracine E.Cardoso D.
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查看更多>>摘要：? 2021 Elsevier Inc.The use of zeolites in basic catalysis is limited when large molecules are involved, such as in the manufacture of fine chemicals, due to difficulty in accessing the micropores of the catalyst. A solution to this problem is to synthesize zeolites containing mesopores that improve the accessibility of the active sites. This work investigates the synthesis of zeolites 4A according to a bottom-up method employing the organosilane surfactant [3-(trimethoxysilyl) propyl] octadecyldimethylammonium chloride (TPOAC), at different concentrations in the synthesis mixture (TPOAC/Al2O3 = 0–0.09), to produce mesopores. The zeolites were evaluated in the Knoevenagel condensation reaction, which is strongly influenced by the accessibility of the catalytic sites, due to the large sizes of the molecules involved. Zeolites 4A with mesopores, showing higher external surface areas, were formed in the presence of TPOAC at the different concentrations tested. Higher conversions were achieved using the zeolites with mesopores, compared to conventional zeolite 4A, due to improved access of the reactant molecules to the catalytic sites. In addition, the reaction catalyzed by the zeolite with mesopores had lower activation energy, compared to use of the conventional zeolite 4A.
查看更多>>摘要：? 2021We propose a one-step procedure to stabilize mesoporous silicon nanoparticles in aqueous solutions by polyethylene glycol (PEG) coating during grinding in a planetary ball mill. The milling is done in aqueous medium that allows us to directly obtain the aqueous suspension of PEGylated nanoparticles. The prepared nanoparticles are investigated by means of the scanning electron microscopy, energy dispersive X-ray spectroscopy, low-temperature nitrogen sorption, dynamic light scattering, Fourier transform infrared spectroscopy, Raman and photoluminescence spectroscopy, which reveal the nanoparticle size of 50–100 nm, preservation of the nanocrystallinity and mesopores. The PEGylated nanoparticles are found to be stable in aqueous solution for at least 24 h. The proposed PEGylation method can be used to control the physical properties and stability of mesoporous silicon nanoparticles for biomedical applications.
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