Boudouard reaction under graphene cover on Ni(1 1 1)

Intercalation and reactions of CO under single layer graphene/Ni(111): the role of vacancies

“…In ref. 16, we also inferred the existence at RT of a weakly bonded CO species adsorbed above the graphene layer, confirming our previous finding obtained at low temperatures under UHV. 12…”

“…We mention that, unfortunately, in absence of defects, CO intercalation causes a G component at a very close binding energy (detached G in ref. 16 and 18) which cannot be separated.…”

“…This effect, already observed on pristine G/Ni(111), is ascribed to the transient adsorption of weakly bonded CO, which has the same binding energy, above strongly interacting graphene. 16 Its presence causes a change in the work function, which explains the shift of the E b values of gas-phase CO. 16…”

“…To perform this analysis, we applied the same procedure used in ref. 16 and 21. Since the adsorbed coverage cannot be determined directly from the XPS intensities due to the temperature and pressure dependent attenuation of the photoemission signals, we evaluate them by assuming that the carbon layer is closed.…”

“…XPS spectra were calibrated towards the Fermi Level and fitted following the procedure described in ref. 16.…”