Low-energy electron diffraction, Auger electron spectroscopy, and thermal desorption studies of chemisorbed CO and O2 on the (111) and stepped [6(111) × (100)] iridium surfaces

Etching of graphene on Ir(111) with molecular oxygen

“…To summarize, for a 1 ML, hole-free Gr layer our XPS measurements do not show the presence of any oxygen on the sample after large exposures at increasingly higher temperatures up to the onset of combustion, which occurs around 700 K. In contrast, for a partial Gr coverage with bare metal present, molecular oxygen adsorbs dissociatively on Ir(111) [38], intercalates the Gr layer [30] and etching starts at a markedly lower temperature, around 550 K.…”

“…The resulting dose of 750 L is more than an order of magnitude larger than what is necessary to reach saturation coverage on Ir(111) [38,39].…”

Ethanol Adsorption, Decomposition and Oxidation on Ir(111): A High Resolution XPS Study

“…[19][20][21][22][23][24][25] It was found that CO desorbs between 400 K and 600 K, and that the CO saturation coverage at room temperature equals 7/12 of a monolayer (ML). For oxygen adsorption on IrA C H T U N G T R E N N U N G (111) an O ad saturation coverage of 0.5 ML was observed after exposure to O 2 at 300 K. This knowledge was used to prepare a well-defined, O ad -covered surface in our experiments.…”

“…The C 1s intensities are calibrated using a CO ad covered surface as a reference (coverage 7/12 ML. [19][20][21] ) This provides a rough estimate of the surface coverage for the different species, as photoelectron diffraction is not taken into account. The peak due to molecular ethanol desorption was removed from the m/e = 2 trace using the m/e = 31 desorption trace.…”

Adsorption and dissociation of O2 on Ir(111)

“…At room temperature an exposure of ϳ20 L is sufficient to produce a very sharp such image. 35,36 Prolonged exposure ͑Ͼ100 L͒ results in no new structure, 35,37 which suggests oxygen saturation. Tucker pointed out that a 2ϫ2 overlayer LEED pattern from an fcc͑111͒ substrate surface could be caused either by a p͑2ϫ2͒ surface structure or by three domains of a ͑1ϫ2͒ surface structure rotated 120°with respect to one another.…”