Mechanism of Ammonia Oxidation to Dinitrogen, Nitrite, and Nitrate on 𝛽-Ni(OH)2 from First-Principles Simulations

Mechanism of Ammonia Oxidation to Dinitrogen, Nitrite, and Nitrate on 𝛽-Ni(OH)2 from First-Principles Simulations

27 Oct 2021

Rachelle’s paper on the mechanisms of ammonia oxidation to dinitrogen, nitrite, and nitrate on 𝛽-Ni(OH)2 from first-principles simulations has just appeared online in Electrochemical Science Advances, new Wiley open access journal! This work was led by Prof. Leanne Chen, Computational Electrochemistry Laboratory at the University of Guelph, and is a part of our collaborative series. Stay tuned for more insights in the ammonia electrooxidation theme!

Title:

Mechanism of ammonia oxidation to dinitrogen, nitrite, and nitrate on 𝛽-Ni(OH)2 from first-principles simulations

DOI: 10.1002/elsa.202100142

Abstract

The electrocatalyzed ammonia oxidation reaction (AOR) is a potential pathway toward waste ammonia remediation, energy generation, and the synthesis of value-added products. To date, mechanistic studies have focused on elucidating the progress of AOR on Pt-based catalysts with an established pathway for N2  only. In this work, density functional theory was applied to determine the lowest energy intermediates toward nitrogen gas, nitrite, and nitrate formation on 𝛽-Ni(OH)2, a promising electrocatalyst material for AOR. It was found that dinitrogen formation progresses via NH-NH coupling, whereas nitrite and nitrate formation occurs via deprotonation of ammonia to form adsorbed N and subsequent hydroxylation to form oxygenated intermediates. This work is the first to report a mechanism for nitrite and nitrate formation and will also serve as a benchmark for future studies on Ni-based materials.