Analysis of the Thermochemistry of NOx Decomposition over CuZSM-5 Based on Quantum Chemical and Statistical Mechanical Calculations

CuZSM-5 is the most active catalyst known for the direct decomposition of NO x . We have performed first-principles quantum mechanical calculations to evaluate the electronic and structural properties of species adsorbed to Cu sites that might be involved in NO x decomposition. Using statistical mechanics, we have calculated Δ U °, Δ H °, and Δ G ° of possible elementary reactions in order to evaluate the stability of adsorbates on Cu sites and the ease of their interconversion. On the basis of these calculations, we propose a reaction pathway for NO x decomposition. This scheme involves only single, isolated copper sites, is internally consistent, and is consistent with experimental observations.