Ammonia Synthesis at Ambient Conditions via Electrochemical Atomic Hydrogen Permeation

Ammonia Synthesis at Ambient Conditions via Electrochemical Atomic Hydrogen Permeation

Ripepi, D. (TU Delft ChemE/Materials for Energy Conversion & Storage)
Zaffaroni, R. (TU Delft ChemE/Materials for Energy Conversion & Storage)
Schreuders, H. (TU Delft ChemE/O&O groep)
Boshuizen, B. (TU Delft ChemE/O&O groep)
Mulder, F.M. (TU Delft ChemE/Materials for Energy Conversion & Storage)

2021

Direct electrochemical nitrogen reduction holds the promise of enabling the production of carbon emission-free ammonia, which is an important intermediate in the fertilizer industry and a potential green energy carrier. Here we show a strategy for ambient condition ammonia synthesis using a hydrogen permeable nickel membrane/electrode that spatially separates the electrolyte and hydrogen reduction side from the dinitrogen activation and hydrogenation sites. Gaseous ammonia is produced catalytically in the absence of electrolyte via hydrogenation of adsorbed nitrogen by electrochemically permeating atomic hydrogen from water reduction. Dinitrogen activation at the polycrystalline nickel surface is confirmed with 15N2 isotope labeling experiments, and it is attributed to a Mars-van Krevelen mechanism enabled by the formation of N-vacancies upon hydrogenation of surface nitrides. We further show that gaseous hydrogen does not hydrogenate the adsorbed nitrogen, strengthening the benefit of having an atomic hydrogen permeable electrode. The proposed approach opens new directions toward green ammonia.

http://resolver.tudelft.nl/uuid:0f99b3eb-def8-4f7e-8ab6-443792760bd3

https://doi.org/10.1021/acsenergylett.1c01568

2380-8195

ACS Energy Letters, 6 (11), 3817-3823

Institutional Repository

journal article

© 2021 D. Ripepi, R. Zaffaroni, H. Schreuders, B. Boshuizen, F.M. Mulder