Ni-doped epitaxial graphene monolayer on the Ni(111) surface

TL;DR

This study combines experimental and computational methods to analyze nickel-doped graphene on Ni(111), revealing the formation of Ni centers that could be useful for catalysis.

Contribution

It demonstrates the formation and stability of Ni atoms in graphene on Ni(111), combining STM and DFT to identify defect structures and charge states.

Findings

Ni centers are formed during graphene synthesis on Ni(111).

Ni atoms are identified as positively charged in graphene.

Ni atoms remain in graphene after detachment from substrate.

Abstract

Nickel-doped graphene has been synthesized from propylene on a Ni(111) surface and studied using scanning tunneling microscopy (STM) and density functional theory (DFT). It is established that nickel centers are formed during graphene synthesis on the Ni(111) surface by both chemical vapor deposition (CVD) and temperature-programmed growth (TPG); apparently, they are always present in graphene synthesized on Ni(111). The centers are observed in STM images as single defects or defect chains and identified by DFT calculations as Ni atoms in carbon bivacancies. These nickel atoms are positively charged and may be of interest for single-atom catalysis. The incorporated Ni atoms should remain in graphene after the detachment from the substrate since they bound more strongly with carbon atoms in graphene than with substrate nickel atoms.