Electrochemical synthesis of Cr(II) at carbon electrodes in acidic aqueous solutions

摘要: The electrochemical synthesis of Cr(II) has been investigated on a vitreous carbon rotating disc electrode and graphite felt using cyclic voltammetry, impedance spectroscopy chronoamperometry. results show that in 0.1 M Cr(III) + 0.5 sulphuric acid 1 hydrochloric over an potential range −0.8 to 0.8 V vs SCE, the reaction at electrodes is essentially surface process proton adsorption desorption, without significant hydrogen evolution chromium(II) formation. At potentials more negative than both formation occurred simultaneously. −1.2 reduction controlled mainly by charge transfer rather mass transport. Measurements HCl, with CrCl3, allowed exchange current density Tafel slope for evolution, Cr(II), be determined. chromium(III) can predicted extended high field approximation Butler–Volmer equation, term reflecting conversion rate Cr(II).