Quassi-classical MD study of methane reactivity over spontaneously missing-row reconstructed fcc(110) surfaces: methane/Pt(110) and methane/Ir(110).

H. FABIO BUSNENGO; IVÁN F. PELUDHERO

Santa Fe

Conferencia; San Luis Conference on Surfaces, Interfaces and Catalysis; 2018

UNL

It is well known that late 5d transition-metal (110) surfaces [e.g. Ir(110) and Pt(110)] undergo spontaneous missing-row reconstructions. These processes entail deep changes in the surface structure since alter significantly the coordination of surface atoms with respect to the"ideal" flat unreconstructed surface. In this work we investigate the influence of this type of surface reconstruction on the reactivity of Ir(110) and Pt(110) through Density Functional Theory calculations, taking the dissociative adsorption of methane as a probe. Whereas in the case ofPt(110) the atomic (1x2) structure of the reconstructed surface is well known, in the case of Ir(110) several models involving different numbers of missing rows per unit area have been proposed to rationalize experimental data. Thus, for both metal surfaces but in particular for Ir(110), we have first investigated the relative stability of several structural models of the clean surfaces with (1x1), (1x2) and (1x3) symmetries. Secondly, we have computed the energy of the transition states for the first C-H bond breaking process of methane on these model surfaces in order to elucidate in what extent, the spontaneous missing-row reconstruction determines the reactivity of both, Pt(110) andIr(110). Then by means of Quasi-Classical Molecular Dynamics we studied in detail the reactivity of methane over spontaneous missing-row reconstructed surfaces: methane/Pt(110) and methane/Ir(110). Finally, we discuss on the possibility of developing accurate reactive force fieldsto describe methane dissociation on these reconstructed surfaces in a similar way to the close-pack (111) surfaces.