  Metal nanostructures confined between sp2 hybridized 2D materials and solid
supports are attracting attention for their potential application in new
nanotechnologies. Model studies under well-defined conditions are valuable for
understanding the fundamental aspects of the phenomena under 2D covers. In this
work we investigate the intercalation of iron atoms through a single layer of
mixed graphene and hexagonal boron nitride on Pt(111) using a combination of
spectroscopic and microscopic techniques. Thermally activated diffusion of iron
proceeds preferentially under graphene and only partially under hexagonal boron
nitride areas. When oxygen is coadsorbed with iron, the intercalation rate is
higher, and formation of B2O3 and oxygenated B-C species is observed. Our
results suggest the possibility of confining ferromagnetic layers under
heterostructures of graphene and hexagonal boron nitride with potential
technological implications in the fields of spintronics, magnetic data storage
or chemistry under 2D covers.
