Electrochemical macrokinetics analysis of nitrite electrocatalytic reduction to ammonia

Electrocatalytic nitrite reduction (e-NO2-RR) offers an attractive strategy for industrial green ammonia synthesis. The understanding of electrochemical kinetics is the core to guarantee the efficient operation of e-NO2-RR system. However, the application of the widely used Butler-Volmer equation should be restricted to the constraint of non-mass transfer effects. In this work, an electrochemical macrokinetics equation for mass transfer restriction region was developed based on the traditional macrokinetics thought, which combined the Practical Butler-Volmer equation and Nernst-Plank equation. The model validation was carried out by the combination of multiphysics-field simulation, computational fluid dynamics simulation and experiments, and the results show that the average relative error between experiments and simulations is less than 2%. The results in this article contribute to an in-depth understanding of the kinetics behavior for e-NO2-RR and achieve the extension of electrochemical kinetics equation from non-mass transfer restriction region to mass transfer restriction region.