The utilization of NH3 combustion faces a significant hurdle in mitigating N2O emissions, a potent greenhouse gas. Current deNOx technologies struggle to effectively decompose N2O, especially under practical conditions due to inhibitory effects from exhaust stream components like O2, NOx, and H2O. This study employs first principles investigations to analyze N2O decomposition activity on precious (Ru, Rh), non-precious (Cu, Ni), and hybrid (Ru/Cu, Rh/Cu, Ru/Ni, Rh/Ni) catalysts. Many new Brønsted-Evans-Polanyi relations are established, enabling mechanistic analysis via the Energetic Span Model. The analyses reveal opportunities for enhancing catalytic activity by exploiting weak correlations between intermediates’ free energies. The model captures the inhibitory effects of surface-adsorbed NO on the N2O decomposition activity, aligning well with experimental observations and catalytic trends. The strong binding energy of adsorbed N2/N2O and O adatom is found to be a key descriptor of activity. It is found to aid the catalytic activity in the presence of NO but becomes limiting in its absence.