TY - JOUR
T1 - Graphene Membranes for Atmospheric Pressure Photoelectron Spectroscopy
AU - Weatherup, Robert S.
AU - Eren, Baran
AU - Hao, Yibo
AU - Bluhm, Hendrik
AU - Salmeron, Miquel B.
N1 - St. John's College, Cambridge; Marie Sklodowska-Curie Individual Fellowship (Global) under grant ARTIST from the European Union [656870]; Office of Basic Energy Sciences (BES), Division of Materials Sciences and Engineering, of the U.S. Department of Energy (DOE) [DE-AC02-05CH11231]; Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences of the U.S. Department of Energy (DOE) [DE-AC02-05CH11231]
PY - 2016/5/5
Y1 - 2016/5/5
N2 - 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 O2 (1 bar) but is spontaneously reduced under vacuum. We further demonstrate the detection of various gas-phase species (Ar, CO, CO2, N2, O2) in the pressure range 10-1500 mbar including species with low photoionization cross sections (He, H2). 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.
AB - 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 O2 (1 bar) but is spontaneously reduced under vacuum. We further demonstrate the detection of various gas-phase species (Ar, CO, CO2, N2, O2) in the pressure range 10-1500 mbar including species with low photoionization cross sections (He, H2). 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.
UR - http://www.scopus.com/inward/record.url?scp=84968876713&partnerID=8YFLogxK
U2 - https://doi.org/10.1021/acs.jpclett.6b00640
DO - https://doi.org/10.1021/acs.jpclett.6b00640
M3 - مقالة
SN - 1948-7185
VL - 7
SP - 1622
EP - 1627
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 9
ER -