Surface-Reconstructed Copper Foil Free-Standing Electrode with Nanoflower Cu/Ce2O3 by In Situ Electrodeposition Reduction for Electrocatalytic Nitrate Reduction to Ammonia.

Abstract

The electrocatalytic reduction of nitrate to ammonia (NRA) is considered to be a promising and environmentally friendly alternative to the Haber-Bosch process. Herein, a simple in situ electrodeposition-reduction method is proposed, which allows for the surface reconstruction and modification of copper foil by introducing cerium. The surface modification results in the formation of Cu/Ce2O3 nanoflowers on the copper electrode surface. Additionally, density functional theory calculations demonstrate that Ce2O3 enhances the adsorption of NO3-. Compared with a pure copper electrode, the NRA performance of surface-reconstructed copper is greatly improved, with the maximum ammonia yield rate and the highest Faradaic efficiency from 24.8% to 73.0% and from 0.081 to 0.386 mmol h-1 cm-2, respectively. The 15N isotope labeling experiment confirms that the nitrogen source in the ammonia originated from nitrate.