Understanding Catalytic Activity Trends of Electrochemical Ammonia Oxidation Reaction using Density Functional Theory Calculations and Microkinetic Modeling

Electrochemical ammonia oxidation reaction (AOR) is promising as an alternative anodic reaction to oxygen evolution in water electrolysis system. Herein, we develop a microkinetic model based on density functional theory (DFT) calculations for all possible reaction pathways considering both thermochemical and electrochemical N-N bond formation processes. From the microkinetic analysis, we discover that Faradaic bond formation contributes to AOR more significantly than non-Faradaic counterpart and we observe good agreements with the experimental results. We then construct a kinetic volcano plot using binding energies of two reaction intermediates as descriptors, which suggests a catalyst design strategy. Following this strategy, we enumerate numerous alloy combinations and identify a few promising candidates with higher catalytic activity than the most active monometallic Pt catalyst.