Mechanism and kinetics of catalytic oxidation of CO to CO2 over Ptn+and MPtn-1+, (M=Sn, Rh &Ru; n=3, 4) clusters

• Published in: Molecular catalysis 2021-06, Vol.509, p.111638, Article 111638
• Main Authors: Baruah, Satyajit Dey, Paul, Subrata, Gour, Nand Kishor, Biswakarma, Nishant, Deka, Ramesh Chandra
• Format: Article
• Language: English
• Subjects: Bader charge; CO oxidation; MN12-SX; Ptn+ and MPtn-1+ clusters; Rate constant
• ISSN: 2468-8231; 2468-8231
• DOI: 10.1016/j.mcat.2021.111638

•Catalytic Oxidation of CO to CO2 over Ptn+and MPtn-1+, (M=Sn, Rh &Ru; n=3, 4) Clusters.•MN12-SX, a screened exchange hybrid functional along with Density fitting triple-ξ def2TZVPP basis set.•The adsorption energies of CO and O2 over Ptn+and MPtn-1+ clusters are calculated.•Mechanism and Kinetics are reported for CO oxidation.•Sn-doped Pt clusters may act as a suitable model for designing better CO oxidation catalyst. Quantum chemical studies show the elementary effects of doping in the oxidation reaction of CO over Ptn+ and MPtn-1+ (M=Sn, Rh & Ru; n=3, 4) clusters. We have utilized MN12-SX screened-exchange (SX) hybrid functional in conjunction with def2TZVPP basis set to obtain electronic structures and thermochemical properties of all species involved in the reaction. It is found that the co-adsorptions of CO and O2 on pure Pt3+ and Pt4+ clusters are less exothermic, while doped SnPt2+ and SnPt3+ clusters show the most exothermic behavior. Bader charge analysis reveals the most significant dopant-host charge transfer on SnPt2+ and SnPt3+ clusters in the course of CO oxidation. Furthermore, the kinetics of the CO oxidation reaction is evaluated using transition state theory. The results show that the value of the rate constant is the highest for Sn doped Pt clusters in the first oxidation of CO to CO2 molecule than the other clusters. We have found that among the Sn, Rh and Ru doped cationic Pt clusters for CO conversion, Sn acts as a suitable alloy on Pt catalyst for building future catalytic converters and fuel cell electrode materials. [Display omitted]