Hydrogen Evolution on Copper in H2SO4 Containing Benzotriazole

Abstract

The rate of hydrogen evolution on copper in acidic solutions containing benzotriazole has been investigated. The rate of hydrogen evolution decreased with an increase in concentration of benzotriazole up to about 7 mM. The reaction orders and the Tafel slopes were approximately the same for uninhibited and inhibited copper, indicating that the mechanism of hydrogen evolution was not changed by the presence of benzotriazole. Differential capacitances of uninhibited copper were about 28 μf/cm2, but capacitances of inhibited copper decreased with increasing inhibitor concentration approaching a limiting value of 1 μf/cm2. The adsorption of the organic inhibitor follows Langmuir adsorption behavior with an adsorption constant of 7.2 mM−1.