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Zn(Ta1-xNbx)2O6 pseudo-binary oxide nanocrystalline materials (where x = 1; 0.5; 0.1; 0.05 and 0) were obtained through the solid-state method and characterized by X-ray diffraction, Fourier Transform Infrared Spectroscopy and Ultraviolet-visible spectroscopy. In addition, their morphology and topography have been determined by field emission-scanning electron microscopy (SEM) and atomic force microscopy (AFM). There is a significant dependence between the rugosity and the uniformity of crystals. The evenly crystals organized in multilayers have the lowest value of rugosity and the non uniform fractal type architectures have the highest value of rugosity. The compounds? anti-corrosion features were evaluated after deposition on carbon steel (OL) in 0.1 M Na2SO4 media by open circuit potential measurement and potentiodynamic polarization technique with Tafel representation. The inhibition efficiency of pseudo-binary oxides deposited on carbon steel electrode was in the range 42.3-52.7 % promising for their further multiple layer deposition with porphyrins in order to improve anticorrosion properties. Due to the high band gap (3.80 - 4.30 eV) provided by increasing the tantalum content, four of these pseudo-binary oxides might find applications in photovoltaic cells.

Summary Polyaniline (PANI) based composites and multilayers as well as porphyrin derivatives have been previously reported as efficient anti-corrosion coatings. In our studies, 5,10,15,20-tetra(4-methylphenyl)-21H,23H-porphyrin (TMP) was adsorbed on carbon steel surface before PANI electrodeposition, in order to improve the corrosion protection of PANI films on steel. The corrosion behavior of the TMP-PANI bilayer carbon steel modified electrodes was investigated in 0.1 M H2SO4 solution using electrochemical tehniques. It was found that TMP-PANI coatings can provide a good protection against carbon steel corrosion. The corrosion rate for the composite coated steel was significantly lower than that of the bare steel, and exhibited an inhibition efficiency of ∼80%.

Detection of biologic compounds in particular dopamine is usually based on the complexation between boronic acid groups and diols. For this reason the development of new sensors based on direct monitoring of boronic acid–diol complexation is attractive. A measurable electric response due to a change in the dopamine concentration can be achieved on electrodes modified with boronic groups. In this work a modified electrode has been obtained by electropolymerization of 3-aminophenylboronic acid in aqueous solutions on a preformed polyaniline layer electrochemically deposited on smooth and skeleton nickel electrodes. The modified electrodes have been tested as impedimetric sensors for the detection of dopamine in aqueous phosphate buffer at pH = 7.4. Both sensors gave a linear response for dopamine concentrations between 10−5 and 10−10 mol L−1. Poly(3-aminophenylboronic acid) modified skeleton nickel electrode has the advantage of an increased specific surface area, that lead to a high density of boronic acid groups and hence to a better sensitivity.