How changes in interfacial pH lead to new voltammetric features: the case of the electrochemical oxidation of hydrazine

Antony Cyril Arulrajan (1) , Christophe Renault (2) , Stanley Lai (1)

1 University of Twente
2 LPMC - Laboratoire de physique de la matière condensée

The electrochemical oxidation of hydrazine was investigated in strongly and weakly pH buffered solutions to reveal the role of buffer capacity in proton-electron transfer redox reactions. In sufficiently buffered solutions, a single voltammetric feature was observed. However, increasing the hydrazine concentration (or, equivalently, moving to an insufficiently buffered solution) gave rise to a second voltammetric feature. These results are rationalized with a conceptually simple model and finite element simulations. We demonstrate that the new voltammetric feature is caused by a large change in the pH at the electrode surface as the reaction proceeds. Importantly, we show that the occurrence of additional voltammetric features are general for proton-electron transfer reactions in insufficiently buffered solutions, and should not be confused with changes in the reaction mechanism.

Domaines: Autre

Antony Cyril Arulrajan, Christophe Renault, Stanley Lai. How changes in interfacial pH lead to new voltammetric features: the case of the electrochemical oxidation of hydrazine. Physical Chemistry Chemical Physics, 2018, 20 (17), pp.11787-11793. ⟨10.1039/c8cp01835a⟩. ⟨hal-02389128⟩