Journal of Electroanalytical Chemistry, Vol.660, No.2, 224-229, 2011
Kinetics of the hydrogen evolution reaction on gold electrode. A new case of the barrierless discharge
Kinetics of hydrogen evolution reaction on the electrodeposited gold electrode is studied. In semi-logarithmic coordinates, polarization curves consist of two linear segments with Tafel slopes 0.06 V at lower overpotentials and 0.12 V at the higher ones. The kinetics in the higher-slope region depends on the solution pH and the Psi(1)-potential (effects of the ionic strength and of the presence of the surface-active tetrabutylammonium cation) as it is predicted by the theory of the ordinary slow discharge. In the lower-slope region, overpotential does not depend on pH and Psi(1)-potential; this is in full accordance with the theory of the barrierless discharge. We nevertheless analyze also several alternatives to the theory of barrierless discharge for the explanation of the low-slope region, but we show that they are not consistent with the experimental data. (C) 2011 Elsevier B.V. All rights reserved.
Keywords:Electrodeposited gold;Barrierless discharge;Ordinary discharge;Overpotential;Psi(1)-effect;Overpotential-pH dependence