HYBRID DENSITY FUNCTIONAL AND MOLECULAR MECHANICS STUDY OF THE CO OXIDATION MECHANISM ON FAUJASITE-SUPPORTED AU MONOMERS

摘要

One of the emerging trends in the field of heterogeneous catalysis is the concept of single atom catalysis. Motivated by this, we have studied CO oxidation over faujasite-supported Au monomers in neutral and cationic (+1 and +3) states using the hybrid density functional method. The most favorable pathway, as revealed from the present calculations, involves the Eley-Rideal mechanism with CO adsorbed on the supported Au center and the O_2 molecule reacting from the gas phase. The initial configurations containing CO and O_2 with substantial interaction energies lead to oxidation pathways that entail high reaction barriers and are thus not appreciable. Among the three systems considered here, Au~(3+)/FAU exhibits better catalytic activity, and the stability of all the species including the transition states with respect to the interacting species indicates no thermal activation.