查看更多>>摘要：Fe2O3@CdS photocatalyst has been successfully prepared by photo-deposition of Fe2O3 on the surface of CdS. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results revealed that the Fe2O3@CdS samples consisted of CdS and Fe2O3. The deposited amount of Fe2O3 has an remarkable influence on the photodegradation of tetracycline. The degradation rate of tetracycline was 94.1% under the optimized conditions. The enhanced photocatalytic activity is mainly due to the high dispersion of Fe2O3 deposited on the surface of CdS. The migration path of photocatalytic holes and electrons follows the Z-scheme heterogeneous junction mechanism, which is useful to improve the separation ability of photogenerated electrons-holes pairs. This work provides a new way to construct a photocatalyst with high photocatalytic performance for the photodegradation of tetracycline.
查看更多>>摘要：Tb3+/Eu3+ doped Bi2Sn2O7 phosphors were synthesized by a co-precipitation method. XRD patterns indicate that Tb3+/Eu3+ doped Bi2Sn2O7 have a single phase. TEM images indicate that the phosphors are irregular particles with the size of several nanometers. Tb3+ or Eu3+ singly doped Bi2Sn2O7 phosphors show characteristic photoluminescence of Tb3+/Eu3+ ions while they are excited. And Tb3+/Eu3+ codoped Bi2Sn2O7 phosphors show tunable photoluminescence because of Tb3+ -> Eu3+ energy transfer. The light can move from green region to yellowish-red region via yellow region by changing Eu3+ concentration.
查看更多>>摘要：The development of an efficient ethylene-ethane separation technology is highly necessary and desirable. Selective adsorption of ethylene over ethane using porous aromatic has aroused considerable attention due to their merits of high porosity, excellent stability and tunable structure. We describe the synthesis of a silver functionalized material, PAF-1-PO3Ag2, using a Bronsted acidic porous aromatic framework via ion exchange. This material offers a higher ethylene capacity of 4.05 mmol/g than that for ethane (3.10 mmol/g). In addition, PAF1-PO3Ag2 possesses a high C2H4/C2H6 selectivity of 4.8 at 298 K and 1 bar, thus making it a promising porous adsorbent in ethylene purification.
查看更多>>摘要：An aqueous solution containing polyvinyl alcohol, calcium nitrate and ferric nitrate was electrospun to yield smooth nanocomposite fibers with diameter in the range of 160 nm. As-synthesized nanofibers were heat treated at different temperatures ranging from 400 to 1000 degrees C to remove the organic matter and induce crystallization of CaFe2O4. Room temperature X-ray diffraction studies showed that CaFe2O4 nanowires existed in single phase cubic structure in as-spun nanofibers heat treated up to 500 degrees C. However, a slow transformation of cubic spinel nanostructure to orthorhombic nanostructure was observed when heat treated above 500 degrees C. The sample heat treated at 1000 degrees C for 8 h yielded a single phase orthorhombic CaFe2O4 nanowires. Magnetization curves recorded at low temperatures indicated superparamagnetic behavior in cubic CaFe2O4 nanowires. Super paramagnetism persisted in cubic samples obtained by heat treated as-spun nanofibers up to 500 degrees C. As-spun nanofibers heat treated at 500 degrees C exhibited superparamagnetic characteristics with saturation magnetization of 18.45 emu/g whereas nanofibers heat treated at 1000 degrees C exhibited ferrimagnetic nature with saturation magnetization of 2.19 emu/g.
Abbasi, A.Khan, Sami UllahAl-Khaled, KamelKhan, M. Ijaz...
10页
查看更多>>摘要：The flow of nanoparticles presents many dynamic applications in thermal sciences, solar systems, cooling and heating phenomenon, energy resources and much other multidisciplinary significance. Following to such valuable applications and motivations in mind, this research pronounced the thermal applications of radiative Casson nanoparticles in presence of radiative phenomenon and activation energy. The oblique stagnation point flow has been considered due to the stretching cylinder. To analyze the flow problem, the problem is formulated in the cylindrical coordinates. The numerical solution is computed via bvp4c built solver by using the MATLAB software. The impact of different involved parameters on skin fraction, heat transfer rate and mass transfer rate is reported and discussed in tables.
查看更多>>摘要：This work describes strategies that BiVO4 is introduced to adjust the range of light absorption in the Fenton catalysis. The as-prepared BiVO4/gamma-Fe2O3/bentonite (Bi-Fe-Bt) showed a good absorption in both UV and visible regions. Under the best conditions (10 mM H2O2, 0.20 g/L catalyst, 10% Bi-Fe-Bt), the Bi-Fe-Bt displayed to possess superior degradation ability to Rhodamine B (RhB). The catalyst showed high photocatalytic activity (98%) after five reaction cycles, which showed that the magnetic catalyst possessed very stable, and easy to be separated by an external magnetic field. It can potentially provide a pathway to the Fenton catalyst in water treatment.
查看更多>>摘要：Graphene oxide (GO) sheets were synthesized using tap water as the electrolyte in an electrochemical exfoliation method, that is cost-effective, environmentally friendly and relatively simple. The effects of electrode materials, i.e. carbon fibre sheets and graphite rod, and different intensities of electrical current on the final properties of GO were explored by UV-Vis spectroscopy, Raman spectroscopy, X-ray Photoelectron spectroscopy and transmission electron microscopy measurements. Experimental results showed that highly dispersed GO materials could be successfully prepared even when tap water was used as the electrode, thus avoiding any strong oxidative electrolytes. Furthermore, both the electrode materials and the different intensities of electrical current could influence the properties of the resulting GO materials. When the electrical current increased, the concentration of GO in water also increased with the formation of more defects and carboxyl groups (-O-C--O), but fewer epoxy or hydroxyl groups (-C-O) and a lower oxidation degree. Additionally, an increased current intensity led to the formation of smaller GO particles, with particle size range dependent on the electrodes. Carbon fiber sheets appear to be preferable for large-scale productions of GO due to more controllable size range, significantly higher concentration and fewer overlapped layers when compared to the graphite rods at a given electrical current.
查看更多>>摘要：In this work, the electronic structures and optical properties of AB(3)O(6) (A = Bi, Sb) are examined conducting the first-principles method at crystal and molecular level. The results show that the anionic groups and cation-centered polyhedra exhibit excellent optical properties due to their strong covalent bonds and optical anisotropy. The SbO and BiO groups own different responses of polarization anisotropy and first hyperpolarizability, resulting in different optical properties. Moreover, the states nearby the Fermi level of SBBO give positive and negative contribution to birefringence and SHG, which make it own stronger birefringence and smaller SHG comparison with BIBO.
查看更多>>摘要：Based on critical concentration for flocculation (ccf), zeta potential and surface enhanced Raman scattering (SERS) spectra, we found three distinct adsorbed states of adenine on AuNPs that are protonated cations in pH < pK(a1) (4.2), neutral molecules in pK(a1) < pH pK(a2) (9.8), and deprotonated anions in pH pK(a2). Experimental SERS spectra of adenine and various methyl adenine derivatives in addition to vibrational analysis using DFT calculations indicated that adenine adsorbs on AuNP in a perpendicular orientation via lone pair electrons at N3 and N9 atoms in acidic, neutral and basic pH solutions at the concentration of 10(-5)-10(-6) M, in contrast to a slightly-tilted orientation via -NH2 and N1 (or N7) atoms at lower concentration close to the ccf.
NSTL
Elsevier