Fe intercalation under graphene and hexagonal boron nitride in-plane heterostructure on Pt(111)

Abstract

Metal nanostructures confined between sp 2 hybridized 2D materials and solid supports are attracting attention for their potential application in new nanotechnologies. Model studies under welldefined 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 B 2 O 3 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. * Corresponding authors.

Under-cover stabilization and reactivity of a dense carbon monoxide layer on Pt(111)

“…Both peaks further grow upon an increase in the number of intercalation-annealing cycles. This correlation, as well as the BE values of 532.4 and 192.7 eV for O 1s and B 1s, respectively, unambiguously imply the formation of B–O bonds upon reaction with CO 17,47–50. No oxidation of h-BN by CO has been reported on pure h-BN/Pt(111), thus we infer that the reaction has taken place at the ternary interface between h-BN, graphene, and Pt.…”

“…3d and e. While the main CO desorption from Pt under h-BN occurs between 550 and 590 K, desorption from Pt under graphene begins at a temperature of 350 K. Previous microscopic investigations13,17 showed that h-BN domains grow almost exclusively in one azimuthal orientation with respect to the substrate lattice, whereas smaller graphene domains with different azimuthal orientations are formed. The same phase composition of the studied samples was confirmed by LEED.…”

“…The h-BNG layer when also grown on other metals could serve as a membrane facilitating the investigation of mechanisms and fundamental steps in high-pressure and high-temperature catalytic processes. Furthermore, metallic atoms can be intercalated under h-BNG,17 which opens up the opportunity to further tune catalysis under two-dimensional materials.…”

“…Lateral sizes of the domains are typically as large as a few hundred nm. More details on the growth, structure and chemical composition are described elsewhere 13,14,17. The h-BNG layers prepared for the present work comprised 62 ± 5 and 35 ± 5 at% graphene and h-BN phases, respectively.…”

Graphene Blocks Oxidative Segregation of Iron Dissolved in Platinum: A Model Study

“…This indicated that the deposited material was distributed across both surface regions, i.e., those representing exposed Pt(111) and those covered with Gr. The system was then heated up to 970 K in UHV to promote iron diffusion underneath Gr [ 31 ] and, further, into the subsurface (and partially bulk) region of Pt(111). Figure 3d shows a LEEM image of the sample after all the iron has disappeared from the surface.…”