Inverse kinetic isotope effect of ammonia decomposition over Ru/CeO2 using deuterated ammonia

Abstract

This study investigated the ammonia decomposition mechanism over Ru/CeO₂. Isotopic tests using ND₃ revealed that the rate-determining step involves adsorbed nitrogen atoms on Ru. Moreover, an inverse kinetic isotope effect where ND₃ decomposition was faster than NH₃ was clearly observed. The origin of the inverse effect was explained by the lower D coverage on the catalyst surface compared to H coverage for mitigating the inhibition of ND₃ activation.