Micro-kinetic modeling of NH3 decomposition on Ni and its application to solid oxide fuel cells

This paper presents a detailed surface reaction mechanism for the decomposition of NH3 to H2 and N2 on a Ni surface. The mechanism is validated for temperatures ranging from 700 to 1500 K and pressures from 5.3 Pa to 100 kPa. The activation energies for various elementary steps are calculated using the unity bond index-quadratic exponential potential (UBI-QEP) method. Sensitivity analysis is carried out to study the influence of various kinetic parameters on reaction rates. The NH3 decomposition mechanism is used to simulate SOFC button cell operating on NH3 fuel.

► An elementary step surface kinetics model for the decomposition of NH3 on Ni catalyst is developed using UBI-QEP method. ► The kinetic model is validated with experimental data. ► In order to use the model in direct NH3 SOFC, the developed model is supplemented with hydrogen oxidation mechanism.