Nature of the Electrochemical Properties of Sulphur Substituted LiMn₂O₄ Spinel Cathode Material Studied by Electrochemical Impedance Spectroscopy.

In this work, nanostructured LiMn₂O₄ (LMO) and LiMn₂OS (LMOS1) spinel cathode materials were comprehensively investigated in terms of electrochemical properties. For this purpose, electrochemical impedance spectroscopy (EIS) measurements as a function of state of charge (SOC) were conducted on a representative charge and discharge cycle. The changes in the electrochemical performance of the stoichiometric and sulphur-substituted lithium manganese oxide spinels were examined, and suggested explanations for the observed dependencies were given.

Enhancement of Electrochemical Performance of LiMn₂O₄ Spinel Cathode Material by Synergetic Substitution with Ni and S.

Nickel and sulfur doped lithium manganese spinels with a nominal composition of LiMnNiOS (0.1 ≤ ≤ 0.5 and = 0.

Modification of MCM-48-, SBA-15-, MCF-, and MSU-type mesoporous silicas with transition metal oxides using the molecular designed dispersion method.

Four various mesoporous silicas (MCM-48, SBA-15, MCF, and MSU) were modified by the molecular designed dispersion method using Fe(acac)3, Cr(acac)3, and Cu(acac)2 complexes. The deposition was performed at the same concentration of the metal acetylacetonate (acac) complex in a toluene solution. All as-synthesized samples were investigated by diffuse reflectance infrared Fourier transform spectroscopy, Fourier transform infrared photoacoustic spectroscopy, and thermogravimetric analysis.

Dehydrogenation of ethylbenzene with nitrous oxide in the presence of mesoporous silica materials modified with transition metal oxides.

The novel mesoporous templated silicas (MCM-48, SBA-15, MCF, and MSU) were used as supports for transition metal (Cu, Cr, or Fe) oxides. The catalysts were synthesized using the incipient wetness impregnation, and characterized by low-temperature N2 sorption, DRIFT, photoacoustic IR spectroscopy, UV-vis diffuse reflectance spectroscopy, and temperature-programmed desorption of ammonia. It was shown that the preparation method used results in different distributions and dimensions of the transition metal oxide clusters on the inert support surface.

Catalytic activity of MCM-48-, SBA-15-, MCF-, and MSU-type mesoporous silicas modified with Fe3+ species in the oxidative dehydrogenation of ethylbenzene in the presence of N2O.

MCM-48, SBA-15, MCF, and MSU mesoporous silicas were used as supports for a deposition of Fe oxide species. Iron was introduced using two different methods: the wetness impregnation and the molecular designed dispersion (MDD). The obtained catalysts were characterized with respect to their textural parameters (BET), chemical composition (electron microprobe analysis), and reducibility (TPR).