Elucidating the Mechanism of Electrochemical N2 Reduction at the Ru(0001) Electrode

Autor: Egill Skúlason, Younes Abghoui, Ebrahim Tayyebi
Rok vydání: 2019
Předmět:
Zdroj: ACS Catalysis. 9:11137-11145
ISSN: 2155-5435
Popis: Density functional theory calculations are used to elucidate the mechanism of the nitrogen reduction reaction (NRR) in an electrochemical double layer on the Ru(0001) electrode, where all possible proton–electron transfer steps and N–N scission steps during NRR are considered. The model includes a negatively charged electrode and an explicit solvation bilayer of water including hydronium ion(s). We find that all elementary steps in which a proton is transferred to an adsorbate have small additional barriers on the order of 0.0–0.25 eV at an applied potential of −0.6 V versus the reversible hydrogen electrode. The first proton–electron transfer step where an end-on N2 admolecule is reduced to NNH has a negligible additional barrier, whereas the thermochemical barrier is 0.8 eV at −0.6 V. This elementary reaction step is found to be rate-limiting and potential-limiting for NRR on Ru(0001). We predict that NRR will follow an associative distal pathway where after the third proton–electron transfer, the N–N b...
Databáze: OpenAIRE