DFT studies on Pt3M (M = Pt, Ni, Mo, Ru, Pd, Rh) clusters for CO oxidation

The reaction mechanism of CO oxidation catalyzed by several Pt3M (M = Pt, Ni, Mo, Ru, Pd, Rh) clusters has been investigated with density functional theory calculations in the present work. The reaction prefers to proceed via Langmuir–Hinshelwood mechanism. The calculated barriers for the reactions mediated by bimetallic clusters are comparable with that catalyzed by monometallic Pt4 cluster. According to thermodynamics and kinetics results, CO oxidation can take place readily without thermal activation and the O2 scission to form OCOO* is the rate-determining-step. Pt3Mo exhibits superior catalytic activity for CO oxidation among all those investigated clusters and good adsorption for O2. The different performance of those bimetallic clusters for CO oxidation is scrutinized with aid of molecular orbital and natural bond orbital population analysis.