Thermodynamic and Kinetic Assessment of Mediated Hydrazine Electro-Oxidation in Nonaqueous Medium

Hydrazine oxidation reaction (HzOR) provides an energy-efficient alternative to the oxygen evolution reaction (OER), yielding carbon-free products and minimizing catalyst poisoning. While hydrazine oxidation has been extensively researched in aqueous environments, it remains less explored in organic solvents, and it gains importance because of the recent advancement of ammonia oxidation in nonaqueous media. This study investigates the oxidation of hydrazine in acetonitrile using decamethylferrocene (Fc''), a stable, electron-donating ferrocene derivative. The research focused on reaction kinetics, revealing a first-order dependence on the concentrations of both Fc’’ and hydrazine. Additionally, the impact of pyridine-derived bases on HzOR was examined. Mechanistic insights were developed, and temperature-dependent studies indicated a 4.79 kJ/mol activation barrier for the mediated HzOR. The overpotential for HzOR under the given conditions is found to be 829 mV, which was determined through open-circuit potential (OCP) measurements. Quantitative analyses of the gaseous products were performed, which revealed quantitative hydrogen production. This study significantly adds to the existing literature on HzOR by providing crucial data on its behavior in an organic medium.