Oxygen Vacancy-Rich Nanoporous Cu-CoOx/CC Hybrid Catalyst for Controllable Electrocatalytic Reduction of Nitrate

Electrocatalytic nitrate reduction (ENR) to N2 is a promising approach to eliminate nitrate (NO3--N) for solving the eutrophication of water bodies, but it still faces the significant challenge of exploiting efficient electrocatalysts. Herein, a three-dimensional self-supporting Cu-CoOx/CC hybrid was fabricated based on the oxygen vacancy-rich and interfacial engineering strategies for the purpose of the effective electrochemical conversion of NO3--N to N2. The fabricated hybrid catalyst possessed a unique structure of nanoporous, oxygen vacancy-rich and multi-interface. More importantly, it was effectively competent for the selective reduction of NO3--N to N2. Under the optimized conditions (initial NO3--N concentration: 50 mg/L; pH: 7.0; current density: 20 mA cm-2), the Cu-CoOx/CC exhibited 92.3% NO3--N removal efficiency and 57.8 % N2 selectivity after 3 h electrolysis treatment. Moreover, due to the synergistic coupling of Cu and CoOx, the electrocatalytic NO3--N reduction performances and expected intermediates can be regulated. This work could provide a valuable guidance for the synthesis of highly active and selective ERN hybrid electrocatalysts and the pollution control of water eutrophication.