Low‐cost dye‐sensitized solar cells with ball‐milled tellurium‐doped graphene as counter electrodes and a natural sensitizer dye

This paper presents a facile and economic development of dye‐sensitized solar cells using a nonprecious counter electrode made from ball‐milled tellurium‐doped graphene (Te‐Gr) and a natural sensitizer extracted from Calotropis gigantea leaves. The prepared materials were characterized using various techniques, such as Raman spectroscopy, X‐ray diffraction (XRD), atomic force microscopy (AFM), impedance spectroscopy, and scanning electron microscopy with built‐in energy‐dispersive X‐ray spectroscopy (SEM with EDS). The electrochemical activity of the produced counter electrodes and the impedance of the fabricated cells were examined and discussed to devise plans for future enhancement of cell performance. A clear pattern of improvement was found when using cost‐effective Te‐Gr relative to the costly platinum counter electrodes, especially when compared with cells employing another natural sensitizer. The results show approximately 51% enhancement over chlorophyll‐based cells made from spinach, where the added advantage in our approach is the utilization of an abundant plant extract with little nutritional appeal.     

Geographic Information System-based tools in environmental management

The authors reviewed existing modelling platforms as part of a large study of water and pollution pathways through catchments in Ireland (Irish EPA Pathways project). Worldwide, work on producing catchment management tools (CMTs) has been underway for some time and some of the tools identified here date from as early as 1989. Some of the management problems and model conceptualisations have not changed very much but now there is a stronger emphasis on water quality and more concern about a wider range of contaminants. What has changed substantially is the use of Geographical Information System and Graphical Windows interfaces as technologies supporting a wider practical use of these tools. This review of existing CMTs identified three systems which would be candidates if a CMT had to be deployed immediately in Ireland. All have a rigid catchment model structure and lack the flexibility to include any new scientific information or flow-path conceptualisation that may emerge. The same modelling structure is used for all parts of the catchment, with spatial variation represented by parameter variation only and not variation in model structure. They also have rigid graphical user interfaces which cannot be tailored to match any specific requirements that may emerge from the pathways end-user workshops. Thus a CMT with a more flexible and accessible modelling structure is required if the results of current research are to be incorporated.     

CuI Immobilized on Tricationic Ionic Liquid Anchored on Functionalized Magnetic Hydrotalcite (Fe3O4/HT-TIL-CuI) as a Novel,Magnetic and Efficient Nanocatalyst for Ullmann-Type C–N Coupling Reaction

One of the most important reactions in organic synthesis is Ullmann-type C–N coupling reaction which has been used for preparation of numerous biologically active compounds. In this work, CuI immobilized on tricationic ionic liquid anchored on functionalized magnetic hydrotalcite (Fe₃O₄/HT-TIL-CuI) has been successfully prepared and fully characterized by different techniques, including fourier-transform infrared spectroscopy, vibrating sample magnetometer, thermo gravimetric analysis, transmission electron microscopy, field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, elemental mapping, zeta potential, X-ray diffraction, temperature programmed desorption of ammonia (NH₃-TPD), temperature-programmed reduction and inductively coupled plasma. The results showed that the as-prepared nanocatalyst possesses plate-like morphology with approximate size of 50 nm and superparamagnetic behavior. Also, total acidity and total hydrogen consumption of the nanocatalyst were measured to be 8.5 and 1.41 mmol g^?1, respectively. This nanocatalyst exhibited favorable performance for C–N coupling reaction among a variety of aryl halides and N(H)-heterocycles (benzimidazoles, pyrazoles and triazoles) in the presence of 2.5 mol% of nanocatalyst without any additives under air atmosphere revealing high yields in all cases. Besides, it is noted that in the present system the desired product can be easily and quickly isolated and nanocatalyst also recovered magnetically from the reaction mixture employing a permanent magnet for at least six consecutive trials without a discernible decrease in catalytic activity which makes the proposed methodology appropriate for industrial. The findings demonstrated the advantages of the present method as no need for neutral atmosphere, appropriate times, recyclability of the catalyst, broad substrate scope, minimization of chemical waste, simple purification of products, easy workup process, and high yields.