Regensburg 2022 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 8: Solid-Liquid Interfaces 1: Reactions and Electrochemistry

O 8.5: Vortrag

Montag, 5. September 2022, 11:45–12:00, S054

Investigating Zirconium Nitride Cathodes for the Electrochemical Nitrogen Reduction Reaction — •Teodor Apetrei, Saswati Santra, Verena Streibel, and Ian D. Sharp — Walter Schottky Institut, Technische Universität München, Garching, Germany

The electrochemical nitrogen reduction reaction (NRR) can convert nitrogen to ammonia at ambient conditions. The most critical factor to activate N2 is to cleave the N-N triple bond. Transition metal nitrides have been proposed as electrocatalysts for the NRR, with computational studies predicting that N-N bond cleavage can be facilitated via a Mars-van-Krevelen mechanism. Herein, we experimentally test this prediction by investigating sputter-deposited ZrN thin films for the NRR. Our investigations indicate that small amounts of ammonia are indeed produced when pristine ZrN thin films are used as NRR cathodes. However, we also observe nitrogen loss and electrochemical instabilities, which could indicate a sacrificial rather than catalytic role of ZrN. Hence, to accelerate the rate-limiting N-N bond splitting step and facilitate nitrogen replenishment, we anchor Fe SACs onto ZrN. Our preliminary results indicate that high-temperature attachment of Fe SACs leads to overall smaller current densities. However, electrochemical measurements and comparative XPS and XRD studies of the pre- and post-NRR samples suggest an increased nitrogen stability within the Fe-modified ZrN films and improved electrochemical stability. Whether this Fe-modification also facilitates N-N bond dissociation and boosts the NRR activity is currently investigated.