Nitrogen-functionalized microporous carbon nanoparticles (N-MCNs) are prepared by direct carbonization of a novel polymer obtained from the Schiff base reaction of terephthalaldehyde and ...m-phenylenediamine. The carbonization temperature plays a crucial role in the porosity, surface chemistry and capacitive performance for the carbons. N-MCN850 sample shows a much larger specific surface area of 1938m2g−1, a higher specific capacitance of 397Fg−1 and 145Fg−1 at the current density of 0.1 and 100Ag−1 in 6M KOH aqueous electrolyte, respectively. The results indicate its outstanding capacitive behavior and ultrahigh-rate performance. In addition, the electrode shows excellent cycling stability along with 98% of the initial specific capacitance after 5000 charge/discharge cycles.
Mesoporous carbon microspheres (MCMs) with the diameters of 0.5–2.0
μm and mean mesopore sizes of 2.6–4.0
nm were synthesized by a novel hydrothermal emulsion-activated method. The typical MCMs ...electrode materials have a specific capacitance of 157
F
g
−1 in 6
M KOH aqueous solution at a high current density of 10.0
A
g
−1.
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► Mesoporous carbon microspheres (MCMs) were synthesized by a novel hydrothermal emulsion-activated method. ► The typical MCMs electrode have a specific capacitance of 157
F
g
−1 in 6
M KOH aqueous solution at a high current density of 10.0
A
g
−1. ► The resultant MCMs electrode materials with high current charge and discharge capability provide important prospect for electrode materials in supercapacitors.
Mesoporous carbon microspheres (MCMs) with the diameters of 0.5–2.0
μm, main mesopore sizes of 2.6–4.0
nm and specific surface areas of 449–1212
m
2
g
−1 are synthesized by a novel hydrothermal emulsion-activated method. The typical MCMs as electrode materials have a specific capacitance of 157
F
g
−1 at a high current density of 10.0
A
g
−1 in 6
M KOH aqueous solution. The resultant MCMs electrode materials with high current charge and discharge capability in 6
M KOH aqueous solution provide important prospect for electrode materials in supercapacitors which could offer high power density for electric vehicles.
Nitrogen-doped macro-/mesoporous carbon foams (N-MMCFs) with main macropore of 0.2μm, mesopore of 2.6–4.0nm and specific surface areas of 1205–1808m2g−1 were prepared by employing oil-in-water ...emulsion polymerization and activated method. The typical N-MMCFs have a specific capacitance of 159Fg−1 at a very high current density of 20.0Ag−1. Display omitted
► N-MMCFs with dual-sized pore structures were prepared by emulsion-activated method. ► The typical N-MMCF-3 exhibits large specific capacitance at high current density. ► The N-MMCFs sample is an excellent material for use in supercapacitors.
An oil-in-water (O/W) emulsion system of Span 80–Tween 80/1iquid paraffin/aqueous resorcinol–formaldehyde was manufactured. Nitrogen-doped macro-/mesoporous carbon foams (N-MMCFs) were prepared by the polymerization of this O/W emulsion, followed by carbonization and activation process. As-prepared N-MMCFs were characterized by scanning electron microscopy, infrared (IR) spectra, N2 adsorption and desorption analysis, and electrochemical workstation. The results indicate that the N-MMCFs have main macropore of 0.2μm, mesopore of 2.6–4.0nm and specific surface areas of 1205–1808m2g−1. The contact angle of N-MMCFs for water is about 37.5°, obviously lower than that of MMCFs (72.9°), which suggests that the surface wettability of N-MMCFs is greatly improved due to the incorporation of nitrogen into the carbon framework. Electrochemical measurements show that specific capacitance of a typical N-MMCF as electrode material in 6M KOH aqueous solution is as high as 198Fg−1 at a current density of 1.0Ag−1. Its specific capacitance can still remain 159Fg−1 at a high loading current density of 20.0Ag−1 with the retention of 80.3%, which indicates that the typical N-MMCF as electrode material has a good rate capability. The high current charge and discharge capability offers the promising prospects for the application of N-MMCFs as electrode materials in supercapacitors which could meet the need of high power density.
Monoclinic mesoporous BiVO4 was prepared by using silica aerogel as a hard template. Typical BiVO4 had a specific surface area of 20.9m2g−1 with a pore size of 18.2nm and narrow band gap (Eg=2.05eV). ...Monoclinic mesoporous BiVO4 showed 99% degradation for Rhodamine B under visible light in 120min and maintained up to 97% degradation efficiency after four recycles. Display omitted
•Monoclinic mesoporous BiVO4 was prepared by using SiO2 aerogel as a hard template.•Typical BiVO4 had a specific surface area of 20.9 m2g−1 and a pore size of 18.2nm.•Monoclinic mesoporous BiVO4 photocatalyst showed a narrow band gap of 2.05eV.•BiVO4 had excellent photocatalytic degradation for Rhodamine B under visible light.
In this paper, we report the synthesis of monoclinic scheelite mesoporous bismuth vanadate by an impregnated-template method. Bismuth nitrate pentahydrate and ammonia metavanadate were respectively used as bismuth and vanadium precursors, and mesoporous SiO2 aerogel was used as a hard template. Monoclinic-phase mesoporous BiVO4 was obtained by heat treatment of the precursor/template, followed by NaOH solution etching to remove SiO2 template. The resultant BiVO4 samples were characterized by X-ray diffraction, N2 adsorption and desorption, UV–vis diffuse reflectance spectra, UV–vis spectroscopy, Raman spectroscopy, and transmission electron microscopy. The results indicate that typical BiVO4 sample has pure monoclinic-phase mesoporous structure and possesses a specific surface area of 20.9m2g−1 with a pore size of 18.2nm. The band gap of such mesoporous BiVO4 was estimated to be 2.05eV, making them excellent photocatalytic activities under visible light. The photocatalytic efficiency of the monoclinic mesoporous BiVO4 for the degradation of Rhodamine B under the visible light illumination (λ>400nm) in 120min reaches 99%, Besides, the mesoporous BiVO4 photocatalyst still showed high stability: 97% for Rhodamine B degradation after four recycles.
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•The excess monomer suppresses the deposit output in the UF precipitation reaction.•The structural characteristics of the UF deposit change with the excess monomer.•The nucleation in ...the UF precipitation can be classified by the excess monomer.•The deposit density and water absorption could be related to the excess monomer.•The excess monomer enriches at the end positions of the linear polymeric molecules.
The role of excess monomer (i.e., Urea (U) or Formaldehyde (F)) in UF precipitation reaction was investigated at 28°C. The maximum output of the UF resin deposit was found around the U:F molar ratio 1.0:1.0 and this output decreased if excessive urea (or formaldehyde) was used in the reaction system. The excess monomer was considered to decrease the polymerization degree of UF resin deposit and increased the bonding saturation of its copolymerization monomer as well as the solubility of the UF resin deposit. The Influence of the excess monomer on the lamellar crystallinity of the resultant deposit, involving the polymerization degree and bonding saturation of the monomer, was examined. Three different dynamic regions containing excess monomers were revealed according to the behaviors of the deposit nucleation. The density and water absorption of the UF resin particles were finally demonstrated relative to the dynamic regions in their nucleation reactions.
The fabrication of core–shell structural nanosilica@liposome nanocapsules as a drug delivery vehicle is reported. SiO2 nanoparticles are encapsulated within liposomes by a W/O/W emulsion approach to ...form supramolecular assemblies with a core of colloidal particles enveloped by a lipid bilayer shell. A nanosilica core provides charge compensation and architectural support for the lipid bilayer, which significantly improves their physical stability. A preliminary application of these core–shell nanocapsules for hemoglobin (Hb) delivery is described. Through the H-bonding interaction between the hydroxyl groups on nanosilicas and the amino nitrogens of Hb, Hb–SiO2 nanocomplexes in which the saturated adsorption amount of Hb on SiO2 is 0.47 g g–1 are coated with lipids to generate core–shell Hb–SiO2@liposome nanocapsules with mean diameters of 60–500 nm and Hb encapsulation efficiency of 48.4–87.9%. Hb–SiO2@liposome supramolecular nanovehicles create a mode of delivery that stabilizes the encapsulated Hb and achieves long-lasting release, thereby improving the efficacy of the drug. Compared with liposome-encapsulated Hb and Hb-loaded SiO2 particles, such core–shell nanovehicles show substantially enhanced release performance of Hb in vitro. This finding opens up a new window of liposome-based formulations as drug delivery nanovehicles for widespread pharmaceutical applications.
Melamine-resin microspheres were synthesized at a pH of 4.0 for 20 min and used as silver nanoparticle (AgNP) carriers for surface enhanced resonant Raman scattering (SERRS) detection. An acetic ...acid–treatment reaction was introduced into the fabrication of the final substrate. The SERRS performance of the substrate was effectively optimized by regulating excess formaldehyde and experimental parameters, such as acidity, number of treatments and reaction temperature in the acid-treatment reaction. Based on the SERRS detection, it was declared that a trace amount of oligomers with a certain degree of polymerization is necessary for the construction of SERRS hotspots. In addition, it is important to remove excess oligomers with reference to the synthetic reaction of the polymer materials, given the special role of oligomers and the wide application of polymer materials in SERRS detection.
A series of metal‐modified HZSM‐5 catalysts were prepared by impregnation and were used for ethylbenzene dealkylation of the mixed C8 aromatics (ethylbenzene, m‐xylene and o‐xylene). The effects of ...different supported metals (Pt, Pd, Ni, Mo) on catalytic performance, including reaction conditions, were investigated. The physicochemical properties of catalysts were characterized by means of XRD, BET, TEM and NH3‐TPD. Experimental results showed that metallic modification obviously increased the ethylbenzene conversion and reduced the coke deposition, greatly improving the catalyst stability. The distinction of ethylbenzene conversion depended on the interaction between hydrogenation reactivity and acidic cracking of bifunctional metal‐modified zeolites. Compared with Pt and Ni, Pd and Mo were easier to disperse into HZSM‐5 micropores during loading metals. The acidic density of different metal‐modified HZSM‐5 declined in the following order: HZSM‐5>Pt/HZSM‐5>Pd/HZSM‐5>Ni/HZSM‐5>Mo/HZSM‐5. The activity of ethylene hydrogenation decreased with Pt/HZSM‐5>Pd/HZSM‐5>Ni/HZSM‐5>Mo/HZSM‐5. In comparison, Pd/HZSM‐5 showed the best catalytic performance with both high activity and high selectivity, with less cracking loss of m‐xylene and o‐xylene. Moreover, the following reaction conditions were found to be preferable for ethylbenzene dealkylation over Pd/HZSM‐5: 340°C, 1.5 MPa H2, WHSV 4 h−1, H2/C8 4 mol/mol.
Over metal‐modified HZSM‐5, ethylbenzene was converted to benzene and ethylene owing to dealkylation, and ethylene was converted to ethane through catalytic hydrogenation. Ethylbenzene conversion obviously increased over bifunctional catalyst.
Water-in-oil (W/O) emulsion system of Span 80–Tween 85/
n-heptane–
n-butanol/titania and silica sols–formamide-1, 2-epoxypropane was manufactured. Wet titania–silica gel microspheres (TSGMs) were ...synthesized by the sol–gel process in the W/O emulsion system. Formamide as drying control chemical additive was introduced to improve the pore size uniformity of the wet gels, and 1, 2-epoxypropane was employed to reinforce the wet gel structure. Then the obtained TSGMs were dried directly at ambient pressure condition to prepare titania–silica aerogel-like microspheres (TSAMs). The resultant TSAMs were characterized by scanning electron microscope, transmission electron microscope, X-ray diffraction and Brunauer–Emmett–Teller method. The results indicate that TSAMs possess similar characters of those aerogels prepared through supercritical fluid drying. The TSAMs have mean diameters of around 100
μm, a bulk density of 0.3
g/cm
3, the specific surface area of 415
m
2/g and the pore size distribution between 2 and 35
nm with an average pore size of 15
nm. The TSAMs exhibit excellent photocatalytic activity for the degradation of methylene blue which acts as a simulated aqueous organic pollutant in waste water.
By using a w/o/w double emulsion solvent extraction/evaporation method, liposome-loaded polycaprolactone microspheres were prepared as a drug delivery system for the controlled release of ...flurbiprofen.
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► LPMs were fabricated by using a double emulsion solvent extraction/evaporation method. ► Flurbiprofen liposomes can keep intact inside the microspheres after encapsulation. ► The smaller LPMs with more porous surface have faster cumulative release rate.
We reported the preparation and properties of liposome-loaded polycaprolactone microspheres (LPMs) as a drug delivery system for controlling the release of flurbiprofen. LPMs were fabricated using double emulsion solvent extraction/evaporation method and characterized by scanning electron microscopy, Fourier transform infrared spectrum, X-ray diffraction, differential scanning calorimeter and UV–vis spectrum. The results suggest that LPMs have uniform sizes with pores on the external surface. Liposomes are intactly encapsulated in LPMs, which causes slight change of polycaprolactone from semi-crystalline to less-ordered amorphous. The concentrations of polycaprolactone and polyvinyl alcohol (PVA) and the amount of liposomes can affect the diameter, surface morphology and encapsulation efficiency of LPMs. The diameter of LPMs increases from 80 to 200
μm and the encapsulation efficiency of flurbiprofen in LPMs increases from 36.92% to 48.42% when the concentration of polycaprolactone increases from 0.15 to 0.6
g/mL. However, the larger amount of liposomes promotes the aggregation between emulsion droplets and causes more pores on the surface of LPMs, which leads to lower drug encapsulation efficiency. The presence of PVA stabilizes the emulsion droplets against coalescence. With the increase of PVA concentration, the diameter of LPMs decreases and the amount of flurbiprofen encapsulated in LPMs increases. In vitro release studies suggest the structure and morphology of LPMs have close relationship with drug release kinetics. The smaller LPMs with more porous surface have faster cumulative release rate.
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