Structure, stability and reactivity of neutral bimetallic manganese oxide clusters with CO and NO—a DFT study

Abstract

In this work, the structure, stability and reactivity of neutral bimetallic manganese oxide clusters MnMdO2–4 (Md = Ti, V and Cr) with CO and NO are investigated by means of density functional theory (DFT). The hybrid PBE0 with TZVP basis set is employed to obtain MnMdO2–4 minimum energy structures, reactants, reaction intermediates, transition states and products. Our calculations show that the structural parameters are significantly altered when replacing Mn with Ti, V or Cr. All the clusters considered in this study have higher binding energy per atom, which implies that they are highly stable. Further, these clusters have smaller oxygen dissociation energy than CO2 and NO2. This indicates that the O atom can easily dissociate from these clusters and form CO2 and NO2. Our reactivity study shows that the CO and NO oxidation by MnTiO4 cluster is a favourable reaction. These oxidation reactions are barrierless and thermodynamically and kinetically favourable. Therefore, MnTiO4 can be used as a suitable catalyst for CO and NO oxidation. From this study, it is concluded that the titanium-supported manganese oxide will be a suitable catalyst for the CO and NO oxidation in the condensed phase.