Graphene Membranes for Atmospheric Pressure Photoelectron Spectroscopy

Robert S. Weatherup, Baran Eren, Yibo Hao, Hendrik Bluhm, Miquel B. Salmeron

Research output: Contribution to journalArticlepeer-review


Atmospheric pressure X-ray photoelectron spectroscopy (XPS) is demonstrated using single-layer graphene membranes as photoelectron-transparent barriers that sustain pressure differences in excess of 6 orders of magnitude. The graphene serves as a support for catalyst nanoparticles under atmospheric pressure reaction conditions (up to 1.5 bar), where XPS allows the oxidation state of Cu nanoparticles and gas phase species to be simultaneously probed. We thereby observe that the Cu2+ oxidation state is stable in O-2 (1 bar) but is spontaneously reduced under vacuum. We further demonstrate the detection of various gas-phase species (Ar, CO, CO2, N-2, O-2) in the pressure range 10-1500 mbar including species with low photoionization cross sections (He, H-2). Pressure-dependent changes in the apparent binding energies of gas-phase species are observed, attributable to changes in work function of the metal-coated grids supporting the graphene. We expect atmospheric pressure XPS based on this graphene membrane approach to be a valuable tool for studying nanoparticle catalysis.
Original languageEnglish
Pages (from-to)1622-1627
Number of pages6
JournalJournal of Physical Chemistry Letters
Issue number9
StatePublished - 5 May 2016
Externally publishedYes


Dive into the research topics of 'Graphene Membranes for Atmospheric Pressure Photoelectron Spectroscopy'. Together they form a unique fingerprint.

Cite this