Impact of Li/Na/K Nitrate Electrolytes on Commercial Photoelectrochemical Oxygen Demand Devices

This study investigates the influence of nitrate-based electrolytes─specifically LiNO3, NaNO3, and KNO3─on the performance, reproducibility, and operational efficiency of Photoelectrochemical Oxygen Demand (PeCOD) devices. A systematic evaluation was conducted across three operational concentration ranges to identify the interplay between ionic conductivity, charge transport dynamics, and reaction kinetics. The findings reveal that each electrolyte exhibits distinct advantages depending on the concentration regime, with KNO3 offering superior conductivity and sensitivity in the high-concentration regimes, while preserving equivalent stability and reproducibility under lower concentration conditions than the alternatives. Modeling and analysis of the reaction rates highlight intrinsic electrolyte-specific variations which play a role in the overall sensitivity and selectivity of the system. These insights have significant implications for optimizing PeCOD devices in commercial and environmental applications, paving the way for further innovations in water quality monitoring and related fields.