Chemistry Reference
In-Depth Information
Rh/Au
Pd/Au
Pt/Au
{100} /
300 K
{100} /
500 K
{111} /
300 K
{111} /
500 K
{111} /
500 K
+ Au
adatoms
Fig. 8 Snapshots of molecular dynamic computer simulations of Rh, Pd and Pt vapour deposition
on Au substrates at temperatures of
T ¼
300 K and
T ¼
500 K. The deposition rate is at a rate of
1 atom/ns. The
bottom panel
of column 1 is a MD snapshot of a Rh cluster on the Au{111}
substrate annealed at 500 K for 20 ns with 8 Au adatoms
occur occasionally even at room temperature. The closer packed Au{111} surface
exhibits much greater kinetic stability. In order for mixing at the interface to be
prevented, the rate of Pd deposition should be sufficient to form a stabilising
wetting layer before any substitutions between the metals can occur. This is
consistent with other theoretical calculations conducted for small AuPd clusters,
which indicate that increasing shell thickness can improve the stability of segre-
gated structures [
68
].
