Electroanalytical Methods to Establish the Role of Buffer and Electrolyte Components in Water Denitrification Using a Copper-Based Bioinspired Electrocatalyst

The overuse of fertilizers in modern agricultural practices has contributed to the accumulation of nitrogen oxyanions in water systems. These nitrogen oxyanions, including nitrite and nitrate, pose risks to human and marine health. Of these contaminants, nitrite is especially problematic for aquatic life. Chemical methods for reducing nitrite in water are limited by cost and by the risk of secondary contamination. The electrochemical reduction of nitrite is a promising method to solve these issues. Here we report the electrocatalytic reduction of nitrite to nitric oxide in quantitative Faradaic yields with a copper-based electrocatalyst. Electroanalytical methods enable the discussion of mechanistic details, in particular with respect to the catalyst resting state as well as the unexpected role of the buffer and other electrolyte components on electrochemical activity. This work emphasizes the noninnocence of buffers and other electrolyte components, the choice of which should be of critical importance when evaluating the electrochemical activity of new homogeneous electrocatalysts.