Platinum electrochemical corrosion and protection in concentrated alkali metal chloride solutions investigated by potentiodynamic nanogravimetry

Resumo

Platinum nanogravimetry potentiodynamic profiles in cyclic scans have shown significant dependence on alkali metal chloride concentration and effect of cations. Pt EQCM electrode mass drift in consecutive cyclic scans in 0.5 M LiCl, NaCl and CsCl was negative, similarly to the mass drift in aqueous solutions of H₂SO₄ with HCl additive, and this was due to electrochemical corrosion of platinum. The mass loss was prevented and inverted in 3 M solutions in the negative part of the scan, and the effect was attributed to shells of ion pairs firmly attached to the electrode surface via nonequilibrated Pt surface sites generated in the anodic scan. The increase in mass correlated with the increase in the Butterworth–van Dyke model resistance of quartz crystal resonator.