FeOOH regulation on Cu2O/CoO heterointerfaces toward efficient nitrate electroreduction to ammonia

Electrochemical nitrate into ammonia is a feasible and promising wastewater recovery strategy. In this work, a ternary Cu 2 O/CoO/FeOOH heterogeneous structure catalyst with rich interface has been reasonably designed. In the complex system, the electron-rich Cu active center enhances the adsorption of nitric acid radical ions, while Co and Fe species promote the generation of reacted hydrogen (H*) intermediates. The synergistic effect between multiple active sites effectively reduces the energy barrier of the eight-electron nitrate reduction reaction. Therefore, the optimized catalyst achieved a high Faradaic efficiency (FE) of 95.75% and a significant NH 3 yield of 9.83 mg h −1 cm −2 under the condition at −0.4 V vs. RHE. This study confirms the key role of interface electronic regulation in improving the electroreduction performance of nitrates, and provides a simple and reliable strategy for the rational design and construction of high-efficiency heterogeneous structural electrocatalysts.