Mechanism of CO Intercalation Through the graphene/Ni(111) Interface and Effect of Doping

by D. Perilli, S. Fiori, M. Panighel, H. Liu, C. Cepek, M. Peressi, G. Comelli, C. Africh and C. Di Valentin
J. Phys. Chem. Lett. 2020, 11, pp 8887-8892 View at Publisher
DOI: 10.1021/acs.jpclett.0c02447

TOC_JPCL_2020_DP

Molecules intercalate at the Graphene/Metal interface even though defect-free graphene is impermeable to any atomic and molecular species in the gas and liquid phase, except hydrogen. The mechanism of molecular intercalation is still a big open question. In this letter, by means of a combined experimental (STM, XPS and LEED) and theoretical (DFT) study, we present a proof of how CO molecules succeed in permeating the graphene layer and get into the confined zone between graphene and the Ni(111) surface. The presence of N-dopants in the graphene layer is found to highly facilitate the permeation process, reducing the CO threshold pressure by more than an order of magnitude, through the stabilization of multi-atomic vacancy defects that are the open doors to the bidimensional nanospace, with crucial implications for the catalysis under cover and for the graphene electrochemistry.