Copper 3D-printed electrodes for ammonia electrosynthesis via nitrate reduction

Abstract

Ammonia is critical to the world economy. However, nowadays the production of ammonia is exclusively carried out by the well-known Haber–Bosch process, which is an energy-intensive process that leads to a large amount of CO2 emissions. The search for alternative ammonia production routes is mandatory for a sustainable and zero emissions future economy. Electrochemical nitrate-to-ammonia conversion emerges as a suitable alternative to achieve decentralized ammonia production at a small scale with zero emissions perspective. Here, we fabricate copper electrodes by a three-dimensional (3D) printing technique, which allows for the point-of-use customizable fabrication of electrochemical systems, and use them for nitrate-to-ammonia conversion. By using the fused fabrication filament printing technique, Cu-based electrodes were prepared in an easy, fast, and scalable way from a Cu-containing filament. The electrode was used for nitrate-to-ammonia conversion, obtaining an outstanding faradaic efficiency (FE) of 96.5% and a high ammonia selectivity of 95%. The fabrication of a copper-based electrochemical system for nitrate-to-ammonia conversion paves the way for an on-demand, point-of-use scalable electrochemical system for ammonia production.