Graphene Membranes for Atmospheric Pressure Photoelectron Spectroscopy

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

نتاج البحث: نشر في مجلةمقالةمراجعة النظراء

ملخص

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.
اللغة الأصليةالإنجليزيّة
الصفحات (من إلى)1622-1627
عدد الصفحات6
دوريةJournal of Physical Chemistry Letters
مستوى الصوت7
رقم الإصدار9
المعرِّفات الرقمية للأشياء
حالة النشرنُشِر - 5 مايو 2016
منشور خارجيًانعم

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