Limitations of Electrochemical Nitrogen Oxidation toward Nitrate

The electrocatalytic N2 oxidation reaction (NOR) using renewable electricity is a promising alternative to the industrial synthesis of nitrate from NH3 oxidation. However, breaking the triple bond in the nitrogen molecule is one of the most essential challenges in chemistry. In this work, we use density functional theory simulations to investigate the plausible reaction mechanisms of electrocatalytic NOR and its competition with oxygen evolution reaction (OER) at the atomic scale. We focus on the electrochemical conversion of inert N2 to active *NO during NOR. We propose formation of *N2O from *N2 and *O as the rate-determining step (RDS). Following the RDS, a microkinetic model is utilized to study the rate of NOR on metal oxides. Our results demonstrate that a lower activation energy is obtained when a catalyst binds *O weakly. We show that the reaction is extremely challenging but also that design strategies have been suggested to promote electrochemical NOR.

Automated summary

In this study, the possible reaction mechanisms of electrocatalytic N2 oxidation reaction (NOR) and its competition with oxygen evolution reaction (OER) were investigated using density functional theory simulations. The rate-determining step of converting N2 to N2O was proposed and a microkinetic model was used to study the rate of NOR on metal oxides. Design strategies were suggested to promote electrochemical NOR.