Ammonia is a pollutant present in wastewater and is also a valuable, carbon-free hydrogen carrier. Stripping, recovery, and anodic oxidation of ammonia to produce hydrogen via electrolysis is gaining momentum as a technology, yet the development of an inexpensive, stable catalytic material is imperative to reduce cost. Here, we report on a new nickel-copper (NiCu) catalyst electrodeposited onto a high surface area nickel felt (NF) as an anode for ammonia electrolysis. Cyclic voltammetry demonstrated that the catalyst/substrate combination reached the highest current density (200 mA cm−2 at 20 °C) achieved for a non-noble metal catalyst. A NiCu/NF electrode was tested in an anion exchange membrane electrolyser for 50 h; it showed good stability and high Faradaic efficiency for ammonia oxidation (88%) and hydrogen production (99%). We demonstrate that this novel electrode catalyst/substrate material combination can oxidise ammonia in a scaled system, and hydrogen can be produced as a valuable by-product at industrial-level current densities and cell voltages lower than that for water electrolysis.
Bibliographical noteThis is an open access article under the CC BY license.
FunderThe Authors would like to thank the European Union and the Horizon 2020 Research and Innovation Framework Programme for funding this research under the project REWAISE grant agreement No. 869496. The Authors thank the University of Warwick Seedcorn programme for the access to XPS equipment and data analysis. Authors E. L., L. W., and J. G. would like to thank Severn Trent Water for match-funding the PhD project.
- Ammonia Electrolysis
- Ni-Cu catalyst