Supramolecular network of a framework material supported by the anion-π linkage of Keggin-type heteropolyoxotungstates: experimental and theoretical insights.

A novel inorganic-organic hybrid, {Na[Tb(L)(H2O)4]3(SiW12O40)}·4H2O, in which L = 4-hydroxypyridine-2,6-dicarboxylic acid (chelidamic acid), was prepared and characterized by elemental analyses, Fourier transform infrared spectroscopy, and single-crystal X-ray diffraction. It consists of a trinuclear terbium cluster bonded to a Keggin-type polyoxotungstate. In the terbium cluster three crystallographically equivalent Tb3+ ions are bridged by carboxylate oxygen atoms belonging to three chelidamic acid units to form an equilateral triangle. These triangle units connect to each other through hydrogen-bonding and anion-π interactions. A CSD survey was carried out focusing on the cation and the ligand roles in the structure formation of this type of compounds. Finally, DFT calculations were used to analyse the role of the anion-π interactions that are important in the formation of 1D supramolecular assemblies in the solid state. The noncovalent interaction plot (NCIplot) computational tool has been used to characterize the anion-π interaction.

A review on modified carbon materials as promising agents for hydrogen storage.

Carbon materials have been regarded as promising agents for hydrogen storage because of properties such as their light weight, acceptable affinity of carbon for hydrogen and high specific surface area. We can identify many different carbon materials which have been studied extensively such as activated carbons (AC) graphene sheets (GS), carbon nanotubes (CNTs) and other derivative carbon materials derived from theoretical and experimental methods such as g-C3N4, graphyne and carbon nanolayer. These materials can be modified by additional ingredients like free metals, metal oxides, and alloys to improve their hydrogen storage capacity. In this short review article, we attempt to introduce new, reliable, complete and categorised data for researchers concentrating on articles from the last five years (2013-2017) relating to hydrogen storage.

Structural Sensitivity of Carbon Monoxide Hydrogenation by Nano-Structured Iron Catalyst.

A new size dependence kinetic equation for chain growth factor in Fischer-Tropsch synthesis (FTS) was developed using a thermodynamic analysis method. For evaluation of structural sensitivity of FTS reaction, a series of iron oxide nanoparticles were prepared as a catalyst via precipitation by microemulsion method. The experimental results indicated that the difference between activation energies for propagation and termination reactions (Et-Ep) decreased with decreasing the catalyst particle size. Calculated size dependent model parameters were employed for evaluation of surface tension energy (σ) and size-independent activation energy for chain growth probabilities.

Fischer-Tropsch synthesis with Fe/Cu/La/SiO2 nano-structured catalyst.

Nano-structure Fe2O3, CuO and La2O3 components were prepared by micro-emulsion method and then Fe/Cu/La/SiO2 nano-structure catalyst was prepared by mixing and re-slurring the mixture by tetraethylorthosilicate (TEOS). The catalyst composition was designated in term of the atomic ration as: 100Fe/5.64Cu/0.1La/19Si. Structural characterization of nano-structured Fe2O3, CuO and La2O3 components was performed by Transmission Electron Microscopy (TEM), powder X-ray diffraction, Temperature Programmed Reduction (TPR) techniques. Particle size for obtained components was about 20, 21.6 and 12.6 nm for Fe2O3, CuO and La2O3 respectively determined by using XRD pattern (Scherrer equation) and TEM images. Catalytic activity and product selectivity were conducted in a fixed-bed stainless steel reactor and compared with conventional iron catalyst. The results reveal that reducing particle size of catalyst increased the catalyst performance. Also, olefin/paraffin ratios decreased in comparison with conventional catalyst.