Scalable bottom-up synthesis of Co-Ni–doped graphene
Introducing heteroatoms into graphene is a powerful strategy to modulate its catalytic, electronic, and magneticproperties. At variance with the cases of nitrogen (N)– and boron (B)–doped graphene, a scalable method for in-corporating transition metal atoms in the carbon (C) mesh is currently lacking, limiting the applicative interest ofmodel system studies. This work presents a during-growth synthesis enabling the incorporation of cobalt (Co) alongside nickel (Ni) atoms in graphene on a Ni(111) substrate. Single atoms are covalently stabilized within graphene double vacancies, with a Co load ranging from 0.07 to 0.22% relative to C atoms, controllable by synthesisparameters. Structural characterization involves variable-temperature scanning tunneling microscopy and ab initio calculations. The Co- and Ni-codoped layer is transferred onto a transmission electron microscopy grid, confirming stability through scanning transmission electron microscopy and electron energy loss spectroscopy. Thismethod holds promise for applications in spintronics, gas sensing, electrochemistry and catalysis, and potentialextension to graphene incorporation of similar metals.