Selective ammonia production via nitrite electroreduction over CoFe layered double hydroxides-decorated 3D TiO 2 array

Water-soluble nitrite (NO₂⁻) in wastewater from agricultural and industrial activities poses ecological and health risks, and its electroreduction shows promise for ammonia (NH₃) production, but energy losses from the hydrogen evolution reaction (HER) limit its overall efficiency. In this work, we report the use of CoFe-layered double hydroxides on 3D TiO₂ array (TiO₂@CoFe-LDH/TP) as an effective electrocatalyst for NO₂⁻ reduction. By offering superior *H species supply and hydroprocessing capability, this catalyst achieves an NH₃ yield of 1056.4 μmol h⁻¹ cm⁻² with a 97.4% Faradaic efficiency (FE) at −0.6 V and sustains FE above 87% across a range of applied potentials. Additionally, a 60-h simulated wastewater treatment experiment demonstrates its practical application potential.