Comparative study of CO adsorption on planar and tetrahedral Pt nanoclusters supported on TiO2(110) stoichiometric and reduced surfaces

A. S. MALDONADO; C.I.N. MORGADE; S. B. RAMOS; G.F. CABEZA

JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017

1381-1169

TiO2 is awidely used material due to its electronic and catalytic properties, which areof interest for technological applications. In catalysis it is generally usedas support for different catalyzers, such as for example Pt subnanoclusters giventhat they improve the efficiency of the material.             In this work we use an ab initioDFT+U modeling method to study the structure and energetic of Pt4clusters deposited on rutile TiO2(110) stoichiometric and reduced surfaces.  For the Pt-titania system we examine therelative stability between the flat versus 3D tetrahedral Pt4structures, and characterize the cluster/substrate interaction. We determinetheir equilibrium geometries, adsorption energies, charge transfer effects andelectronic density of states to characterize different aspects of themetal-oxide interaction. For both, the stoichiometric and reduced rutile TiO2(110),we find that the flat square configuration is preferred, as experimentsindicate. In particular, we are interested in the potential activity of thesecluster-supported systems for the oxidation of CO adsorbed on Pt. To examinethis behavior we evaluate the structure, electronic DOS properties and chargetransfer effects for the adsorption of CO on both the flat and tetrahedral Pt4isomers over the stoichiometric and reduced TiO2 rutile surfaces. The results point tothe planar cluster on the stoichiometric surface as the most stableconfiguration for CO adsorption, while for the CO conversion to CO2the tetrahedral Pt4 cluster on the stoichiometric TiO2surface would be the most favorable catalytic substrate.