3d metal oxides

It is known that some spinel-structured 3d-metal oxides are good catalysts for many processes involving electron transfer [12]. However, their low conductivity does not allow for the direct use in the electrode of the battery, and grafting them onto the carbon matrix is also very difficult technical problem. It was found recently that this problem could be solved indirectly, creating the spinel catalytic centers on the surface of carbon by means of adsorption of some 3d-metal complexes on the graphite surface followed by subsequent pyrolysis at certain temperatures [13,14],... 

On the basis of obtained data of cyclic voltammograms for 3d metals oxides electrodeposition the optimal conditions (current density, potential, process time, electrolyte composition, temperature) for dense oxide films (Ni, Cr and Co) deposition on steel foil have been elaborated. Data relating to several best films are summarized in Table 1. 

We managed to obtain dense and solid thin films of 3d-metal oxides using the techniques of electrochemical deposition from aqueous fluorine-containing electrolytes. The films have been studied as a possible cathode material for secondary cells. The best samples show good cycle retention and acceptable specific capacity in the range of 180 mAh/g. They also feature a plateau of electrochemical potential at approximately 3,5 V, which is acceptable for present industrially produced electrochemical devices. 

There are many computational investigations of transition metal oxides, see, e.g., the recent review by Harrison [7]. Some studies have included the whole sequence of 3d metal oxides. In one of these studies, Bauschlicher and Maitre [17], employed different high-level ab initio methods. It was found that ScO - MnO and CuO were well described by single-reference based techniques and that the CCSD(T) method gave spectroscopic constants (re, uje and D0) in good agreement with experiments. For FeO - NiO multi-reference based techniques (CASSCF/ICACPF) were necessary to get good results. 

In this study of the 3d metal oxides (ScO - ZnO) the popular hybrid functional B3LYP was used. The Gaussian 94 [20] and Gaussian 98 [21] programs were used. In these, the B3LYP exchange-correlation functional is of the form [22] ... 

The catalytic activity of these simple oxides has been correlated [38,39] with its ability to chemisorb simple molecules such as CO and N20 via an electron transfer, which results in a change in the electron transport properties in the semiconductor solid oxide. In this sense, the catalytic activity of simple oxides has been correlated with the band gap, and the number of d-electrons for 3d metal oxides [22],... 

Simple 3d-metal oxides with Fe, Co, Ni, and Cu as metal have long been disregarded as possible reversible electrode materials for... 

Finally, it should be mentioned that a matrix shift is observed between the frequencies of the vibrational modes in the matrix and in the gas phase. This shift is similar to the solvent shift in solution, and can be modeled by an electrostatic model (the dielectric constant is then the host-dependent parameter). However, in some cases the matrix host could also chemically interact with the isolated species. Such an interaction is observed not only for Xe (which one generally avoids as the matrix host because of its chemical reactivity) but in some cases also for other noble gas matrixes, for example, Ar. An example are the late 3d metal oxides in noble gas matrixes, where the spectra point to a weakly bound complex NgMO (Ng = Ar,Kr,Xe) [38]. 

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