Converting ammonia into hydrazine represents a promising strategy for addressing the demand for energy-dense fuels. Hydrazine, with a notably high energy density of 19.4 MJ/L as a liquid at 1 bar, emerges as a sustainable fuel option sourced from ammonia-rich wastewater streams. As an energy carrier, it is already used in specialized applications such as fighter jets, and it can be easily oxidized and converted into nitrogen gas and electricity. Traditional hydrazine synthesis relies heavily on oxidants such as bleach or hydrogen peroxide, necessitating extensive industrial infrastructure and spatial separation between production facilities. In our research, we developed a modular, small-scale electrochemical system capable of locally synthesizing hydrazine with minimal waste under ambient conditions. We report an electrochemical bleach production cell achieving a ~60% Faradaic efficiency at a ~2.4 V cell potential, producing bleach concentrations up to ~2 M. We also demonstrate azine production achieving an overall faradaic efficiency of approximately 30% using optimized tandem processes to generate hypochlorite and subsequently react with ammonia and ketones to form azine. In this work, we further explore optimization strategies, including improving the performance of semi-batch bleach production and the careful selection of ketones to balance yield and extraction efficiency. This electrochemical method is advantageous at small scales compared to existing industrial methods due to its high efficiency, modularity, environmental compatibility, and economic scalability potential.
