2,859 publications from this institution
In this paper, nanostructured CoP with different morphologies, including nanowires, nanosheets and nanoparticles, were prepared through an organic solvent-free low-temperature phosphidation reaction under Ar. These nanostructures were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller specific surface area measurements. We further studied their electrocatalytic properties towards the hydrogen evolution reaction in acidic media and found that CoP nanowires exhibited the highest catalytic activity and stability.
Three new azomethine dyes were synthesized via a simple condensation method using 2-amino-4,5,6,7-tetrahydro-benzo[b]thiophene-3-carbonitrile and a variety of aldehydes. The structures of synthesized compounds were established by spectroscopic (FT-IR, 1H NMR, 13C NMR, MS) and elemental analyses. UV-Vis and fluorescence spectroscopy measurements proved that all compounds have good absorbance and fluorescence properties. Fluorescence polarity studies demonstrated that these compounds were sensitive to the polarity of the microenvironment provided by different solvents. In addition, spectroscopic and physicochemical parameters, including singlet absorption, extinction coefficient, Stokes shift, oscillator strength and dipole moment, were investigated in order to explore the analytical potential of the synthesized compounds. Three-dimensional structures were studied using single crystal x-ray diffraction. Optimized geometries, electronic structure and frontier molecular orbital energies were studied theoretically, and the energy gap (ΔE) of II was found to be relatively greater than those for I and III, while I and III have almost the same energy gaps.
Seven fluorescent pyrazolines were synthesized. pyrazoline derivatives 5a-g was obtained by cyclization of chalcones 3a-g with phenylhydrazine using various synthetic methods including traditional method and green methodologies such as microwave heating and ultrasound irradiation. The reaction time, product yields are improved using the green methods. The structures were established based on IR spectra, 1H-, 13C NMR, elemental analysis, X-Ray Crystal Structure Determination, UV visible spectra and fluorescence spectra.). The seven compounds showed an excellent fluorescence in various solvents. The fluorescence properties such as quantum yield were measured. The substitution on both aromatic rings showed a remarkable influence on the fluorescence properties, this was rationalized using theoretical calculations of the charge density of both HOMO and LUMO orbitals. This new pyrazolines are potential fluorescent markers for biological systems.
Electroreduction of carbon dioxide (CO<sub>2</sub>) in a flow electrolyzer represents a promising carbon-neutral technology with efficient production of valuable chemicals. In this work, the catalytic performance of polycrystalline copper (Cu), Cu<sub>2</sub>O-derived copper (O(I)D-Cu), and CuO-derived copper (O(II)D-Cu) toward CO<sub>2</sub> reduction is unraveled in a custom-designed flow cell. A peak Faradaic efficiency of >70% and a production rate of ca. -250 mA cm<sup>-2</sup> toward C<sub>2+</sub> products have been achieved on all the catalysts. In contrast to previous studies that reported a propensity for C<sub>2+</sub> products on OD-Cu in conventional H-cells, the selectivity and activity of ethylene-dominated C<sub>2+</sub> products are quite similar on the three types of catalysts at the same current density in our flow reactor. Our analysis also reveals current density to be a critical factor determining the C-C coupling in a flow cell, regardless of Cu catalyst's initial oxidation state and morphology.
