Electrochemical and Structural Properties of Ni(II)-alumina Composites as an Annealing Temperature Function
Alumina powders, pure and doped with nickel, were synthetized by sol-gel method and calcined at 500, 900 and 1100 oC in order to obtain mesoporous structures with a high speciﬁc surface area, well adaptable to catalytic application. The characterization of samples was performed by XRD, EPR spectroscopy and electrochemical impedance spectroscopy (EIS). XRD analysis showed that the addition of Ni2+, as well as the annealing temperature, affects the structural properties of the obtained composites. EPR analysis revealed the traces of Fe3+ impurities, the presence of oxy defects in alumina and Ni2+ in tetrahedral position for samples calcined at 1100 oC. The impedance of the Nafion/alumina modified GCE depended on combined effect of porous structure and surface properties of alumina samples. The electrochemical behavior of a glassy carbon electrode modified with Ni (II)-doped aluminas was studied in 0.5 M NaOH solution, with and without methanol. The electrochemical activity of nickel-doped alumina composites was dictated by the amount of present NiO impurity.
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