Bulk structures of PtO and PtO_ {2} from density functional calculations

Ricardo K. Nomiyama,1 Maur´ıcio J. Piotrowski,2 and Juarez L. F. Da Silva3

1Instituto de Qu´ımica de Sao Carlos, Universidade de S ˜ ao Paulo, Caixa Postal 780, 13560-970, S ˜ ao Carlos, SP, Brazil ˜

2Departamento de F´ısica, Universidade Federal de Santa Maria, 97105-900, Santa Maria, RS, Brazil

3Instituto de F´ısica de Sao Carlos, Universidade de S ˜ ao Paulo, Caixa Postal 369, 13560-970, S ˜ ao Carlos, SP, Brazil ˜

 (Received 6 May 2011; revised manuscript received 23 July 2011; published 14 September 2011)

Abstract

Platinum plays an important role in catalysis and electrochemistry, and it is known that the direct interaction of oxygen with Pt surfaces can lead to the formation of platinum oxides (PtOx), which can affect the reactivity. To contribute to the atomistic understanding of the atomic structure of PtOx, we report a density functional theory study of the atomic structure of bulk PtOx (1≤x≤2). From our calculations, we identified a lowest-energy structure (GeS type, space group Pnma) for PtO, which is 0.181 eV lower in energy than the structure suggested by W. J. Moore and L. Pauling [ J. Am. Chem. Soc. 63 1392 (1941)] (PtS type). Furthermore, two atomic structures were identified for PtO2, which are almost degenerate in energy with the lowest-energy structure reported so far for PtO2 (CaCl2 type). Based on our results and analysis, we suggest that Pt and O atoms tend to form octahedron motifs in PtOx even at lower O composition by the formation of Pt-Pt bonds.

https://www.researchgate.net/publication/235587213_Bulk_structures_of_PtO_and_PtO_2_from_density_functional_calculations