Publications

The effect of solvents on the absorption and emission spectra of 1,4-bis(5-phenyl-2-oxazolyl)benzene (POPOP) laser dye has been studied in various solvents at 298 K. A bathochromic shift was observed in absorption and fluorescence spectra upon increase of solvent polarity, which indicates that this transition is - * . The ground and excited state dipole moments were calculated as 2.23 and 6.34 Debye, respectively. The dye solution in MeOH, n-heptane, and methyl isobutyl ketone gives laser emission in the blue region upon excitation by a 337.1 nm nitrogen pulse; the gain coefficient and emission cross section as well as normalized photostability have been determined. Excitation energy transfer from POPOP to rhodamine B and fluorescine was studied to improve the laser emission from these dyes. Such an energy transfer dye laser system (ETDL) obeys a long range columbic energy transfer mechanism with a critical transfer distance, R 0 , of 25 and 33 and k q equal to 10.4 10 12 and 26.2 10 12 M -1 s -1 for the POPOP/RB and POPOP/fluorescine pair, respectively. The POPOP dye is highly photostable in polar protic and polar aprotic solvents, while it displays photodecomposition in chloromethane solvent via formation of a contact ion pair. The photochemical quantum yield and rate of photodecomposition depend on the electron affinity of solvent.

Abstract A simple one‐step reaction of [60]fullerene with cinnamaldehydes and primary/secondary amines without the addition of any inorganic salts afforded rare arylvinyl‐substituted fulleropyrrolidines in moderate to good yields with high stereoselectivity. Secondary amines produced N ‐alkyl‐2/5‐arylvinyl fulleropyrrolidines with a preference of trans isomers as major products, while primary amines exclusively gave 2‐aryl‐5‐arylvinyl fulleropyrrolidines as cis isomers. A plausible formation mechanism for fulleropyrrolidines was proposed to elucidate the above reaction process.

The synthesis of NH₃ is mainly dominated by the traditional energy-consuming Haber-Bosch process with a mass of CO₂ emission. Electrochemical conversion of N₂ to NH₃ emerges as a carbon-free process for the sustainable artificial N₂ reduction reaction (NRR), but requires an efficient and stable electrocatalyst. Here, we report that the Mo₂C nanorod serves as an excellent NRR electrocatalyst for artificial N₂ fixation to NH₃ with strong durability and acceptable selectivity under ambient conditions. Such a catalyst shows a high Faradaic efficiency of 8.13% and NH₃ yield of 95.1 μg h^-1 mg^-1 _cat at -0.3 V in 0.1 M HCl, surpassing the majority of reported electrochemical conversion NRR catalysts. Density functional theory calculation was carried out to gain further insight into the catalytic mechanism involved.

Herein, green porphyrin sensitizer Y350‐based dye‐sensitized solar cells (DSCs) with binary ionic liquid–based electrolytes are studied, which are a mixture of 1‐methyl‐3‐propyl‐imidazolium iodide and 1‐methyl‐1‐butylpyrrolidinium bis(trifluromethylsulfonyl) ‐imide, 1‐butylpyridinium bis(trifluromethylsulfonyl)imide, 1‐methyl‐3‐ethylimidazolium bis(trifluromethylsulfonyl)imide, or 1‐methyl‐3‐ethylimidazolium tetracyanoborate. The best semitransparent green DSC device exhibits a short‐circuit photocurrent density of 9.1 mA cm −2 , an open‐circuit photovoltage of 727 mV, and a fill factor of 70%, corresponding to an overall power conversion efficiency (PCE) of 4.9% under standard AM 1.5G illuminations at 100 mW cm −2 . The PCE increases to 6.1% with opaque films containing larger light‐scattering TiO 2 particles.

Polypyrrole (PPy) and polypyrrole/cerium oxide nanocomposite (PPy/CeO₂) were prepared by the chemical oxidative method in an aqueous medium using anhydrous ferric chloride (FeCl₃) as an oxidant. The successful formulation of materials was confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmittance electron microscopy (TEM). A four-in-line probe device was used for studying DC electrical conductivity and ammonia vapor sensing properties of PPy and PPy/CeO₂. The significant improvement in both the conductivity and sensing parameters of PPy/CeO₂ compared to pristine PPy reveals some synergistic/electronic interaction between PPy and cerium oxide nanoparticles (CeO₂ NPs) working at molecular levels. The initial conductivity (i.e., conductivity at room temperature) was found to be 0.152 Scm^-1 and 1.295 Scm^-1 for PPy and PPy/CeO₂, respectively. Also, PPy/CeO₂ showed much better conductivity retention than pristine PPy under both the isothermal and cyclic ageing conditions. Ammonia vapor sensing was carried out at different concentration (0.01, 0.03, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 vol %). The sensing response of PPy/CeO₂ varied with varying concentrations. At 0.5 vol % ammonia concentration, the % sensing response of PPy and PPy/CeO₂ sensor was found to be 39.1% and 93.4%, respectively. The sensing efficiency of the PPy/CeO₂ sensor was also evaluated at 0.4. 0.3, 0.2, 0.1, 0.05, 0.03, and 0.01 vol % ammonia concentration in terms of % sensing response, response/recovery time, reversibility, selectivity as well as stability at room temperature.

In this paper, for the first time, we report on the growth of ultrathin Ni(OH)2 nanosheet arrays on a nickel foam (NF) via a novel pH-driven dissolution–precipitation route, carried out by a hydrothermal treatment of the NF in an acidic medium without the introduction of other nickel sources. Acid etching of the NF surface leads to nano-pits and produces Ni(H2O)n2+ ions at the early stage of the reaction. With the elapsed time, an increase in the pH level occurs and the Ni(H2O)n2+ ions gradually hydrolyze and preferentially precipitate on the nano-pits, serving as nucleation sites and leading to ultrathin Ni(OH)2 nanosheet arrays on an NF. The effects of the experimental parameters, such as reaction time, acid type and starting pH value, on the Ni(OH)2 growth are also investigated. Because the nano-pits are integrated parts of the NF and the deposition of Ni(OH)2 nanosheets on such nano-pits ensures intimate contact between them, the Ni(OH)2/NF is robust enough to withstand a violent sonication process and efficient and rapid electron transfer is achieved. As a binder-free anode for Li-ion batteries, the Ni(OH)2/NF exhibits an unexpected ultrahigh capacity of 1689 mA h g−1 and excellent cycling stability.

Highly effective removal of toxic pollutant microcystins from water sources is achieved by employing ordered mesoporous carbons prepared from the surfactant-templating method as adsorbents. For the first time, a systematic study into the static and dynamic adsorption behaviours of ordered mesoporous carbons towards microcystin-LR (MC-LR) is demonstrated. Firstly, by adopting different mesoporous carbons with various mesostructures, textures and surface chemical properties for batch adsorption, definite relationships between the adsorption performance of MC-LR and properties of adsorbents are established. Among all the samples, the mesoporous carbon (MCS/C) obtained from a mesoporous silica–carbon composite after removing the silica component exhibits an unprecedented adsorption capacity of ∼526 mg g−1, due to its unique bimodal mesopores of ∼2.8 and 5.8 nm, a high surface area of 1680 m2 g−1, a large pore volume of 1.67 cm3 g−1 and two-dimensional (2D) straight mesopore channels. A comprehensive understanding of dynamic adsorption behaviour shows that this mesoporous carbon possesses a 30-fold higher adsorption capacity compared with powdery activated carbon at a high flux of 120 L m−2 h−1. Finally, two pollutants, Rhodamine B and phenol, are mixed with MC-LR for competitive adsorption onto the mesoporous carbon MCS/C. It is found that the total amount of removal pollutants increases sharply to ∼700 mg g−1. Considering all the advantages, the ordered mesoporous carbon MCS/C shows a promising potential for practical waste water treatment, especially for large toxin microcystin removal.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.