Formation of Pt and Rh Nanoclusters on a Graphene Moire Pattern on Cu(111)

摘要

The formation of Pt and Rh nanoclusters on a graphene moire pattern on Cu(111) was studied with ultrahigh vacuum scanning tunneling microscopy (UHV-STM). Isolated graphene islands with different periodicities were successfully grown on the Cu surface. As a result of weak coupling to the Cu substrate, different graphene rotational domains were observed including one with a periodicity of 4 nm that has not been previously reported. Furthermore, our results have shown that Pt and Rh form dispersed nanoclusters on graphene/Cu(111) with Pt forming more regular structures trapped mostly at the hollow sites. This variation in growth behavior is mainly attributed to differences in Pt—carbon and Rh— carbon interaction energies. Thermal stability experiments were also performed, and Pt clusters were found to be structurally stable up to 700 K.