Selective ammonia production via nitrite electroreduction over CoFe layered double hydroxides-decorated 3D TiO <sub>2</sub> array
Yi Liang, Xiaoya Fan, Xun He, Dongdong Zheng, Shengjun Sun, Yongsong Luo, Hao Chen, Xuping Sun
Abstract
Water-soluble nitrite (NO<sub>2</sub><sup>−</sup>) in wastewater from agricultural and industrial activities poses ecological and health risks, and its electroreduction shows promise for ammonia (NH<sub>3</sub>) 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 TiO<sub>2</sub> array (TiO<sub>2</sub>@CoFe-LDH/TP) as an effective electrocatalyst for NO<sub>2</sub><sup>−</sup> reduction. By offering superior *H species supply and hydroprocessing capability, this catalyst achieves an NH<sub>3</sub> yield of 1056.4 μmol h<sup>−1</sup> cm<sup>−2</sup> 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.