Structure of thePd8Ni92(110)catalytic surface from first principles

Abstract

We have used spin-polarized density functional theory calculations to investigate the structure of the ${\mathrm{Pd}}_{8}{\mathrm{Ni}}_{92}(110)$ alloy surface, which has been extensively studied for its excellent catalytic properties. Our calculations have corroborated that this alloy has a quite complex ($N\ifmmode\times\else\texttimes\fi{}1$, $N\ensuremath{\sim}6$) structure, so-called ``sawtooth'' (ST) reconstruction. Moreover, we have accurately computed the metal-metal bond distances and the interlayer spacings. We have also proved that the inclusion of the spin-polarization effects is crucial for a good description of the energetics. Our results agree nicely with those arising from scanning tunneling microscopy and surface x-ray diffraction experiments. In addition, our model brings insights into the driving forces leading to the ST reconstruction.