Comparative study on the direct decomposition of nitrous oxide over M (Fe, Co, Cu)–BEA zeolites

Catalytic activities of M (Fe, Cu, Co)–beta (BEA) zeolites for N2O direct decomposition were systematically investigated by employing both experimental and theoretical [density functional theory (DFT)] approaches. The activities of M–BEA determined by intrinsic kinetic evaluations are in good agreement with the DFT calculations and the microkinetic analyses, revealing that the distinguishing activities of M–BEA were mainly attributed to their distinct energy barriers for the O2 desorption (Part 3). During the DFT calculations, a unique intermediate (IM) was generated only over Co–BEA, which was verified by the activity evaluation and N2O-TPD experiments, showing that the formation of IM reduced N2O decomposition rate of Co–BEA. The negative effect of the IM was thereafter investigated by the microkinetic analyses through which it was known that the second forward reaction rate constant of Co–BEA was lower than its reverse reaction rate constant, resulting in a final decline of the N2O decomposition rate.