Oxygen vacancy-regulated nanorod array electrodes for boosting the electrocatalytic synthesis of ammonia from nitrate wastewater.

The adsorption of nitrate is the key to enhancing the electrocatalytic nitrate reduction reaction (NitRR). Herein, a typical hydrolysis-coupled redox (HCR) reaction has been designed to prepare unique 3D Cu/FeO core-shell nanorod array cathodes with controllable oxygen vacancy concentrations for NitRR. The optimal Cu/FeO-13 achieves a high nitrate conversion of 99.10% and ammonia selectivity of 98.30%. The outstanding electrochemical performance is attributed to the enhancement mechanism of OVs and a unique nanorod array structure with a high density of surface-exposed OVs and high-throughput transport pathways for ion-aspects.