Browsing by Subject "azotan"

Now showing 1 - 2 of 2

Access status: Open Access ,
Electrochemical behavior of tellurium in acidic nitrate solutions
(2014) Rudnik, Ewa; Biskup, Przemysław
Electrochemistry of tellurium stationary electrode was studied in acidic nitrate solutions with pH 1.5 – 3.0. Cyclic voltammetry indicated that two products were formed at potentials above 300 mV (SCE): soluble $HTeO_{2}^{+}$ (500 mV) and sparingly soluble $H_{2}TeO_{3}$ (650 mV), but the former seemed to be an intermediate product for $TeO_{2}$ precipitation on the electrode surface. Formation of the solid products as porous layers was almost undisturbed and no electrode passivation was observed. $H_{2}TeO_{3}$ and $TeO_{2}$ dissolved to $HTeO_{2}^{+}$ under acidic electrolyte, but this process was hindered by pH increase. Cathodic polarization of tellurium electrode below -800 mV was accompanied by evolution of $H_{2}Te$, which was then oxidized at the potentials approx. -700 mV. $H_{2}Te$ generated in the electrochemical reaction decomposed to elemental tellurium as black powdery precipitates in the bulk of the solution and a bright film drifting on the electrolyte surface.
Access status: Open Access ,
Electrodeposition of silver from nitrate-tartrate solutions
(Wydawnictwa AGH, 2018) Rudnik, Ewa
The electrodeposition of silver from AgNO3 solutions with the addition of L-tartaric acid was investigated. The cathodic reaction was accompanied by low electrode polarization and run under activation control for AgNO3 concentrations of above 70 mM. Tartaric acid only slightly shifted the polarization curves towards more electronegative potentials (by approx. 50 mV), but it did not change the rate-determining step. The activation control of the process resulted in the formation of rough and coherent deposits, while the mixed or diffusion control of the process promoted the formation of dendritic-like structures and spongy deposits.