Adsorption of CO2 on Graphene: A Combined TPD, XPS, and vdW-DF Study

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• 作者：Kaori Takeuchi ; Susumu YamamotoYuji Hamamoto ; Yuichiro Shiozawa ; Keiichiro Tashima ; Hirokazu Fukidome ; Takanori Koitaya ; Kozo Mukai ; Shinya Yoshimoto ; Maki Suemitsu ; Yoshitada Morikawa ; Jun YoshinobuIwao Matsuda
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：February 9, 2017
• 年：2017
• 卷：121
• 期：5
• 页码：2807-2814
• 全文大小：437K
• ISSN：1932-7455

文摘

The adsorption of CO₂ molecules on monolayer epitaxial graphene on a SiC(0001) surface at 30 K was investigated by temperature-programmed desorption and X-ray photoelectron spectroscopy. The desorption energy of CO₂ on graphene was determined to be (30.1–25.1) ± 1.5 kJ/mol at low coverages and approached the sublimation energy of dry ice (27–25 kJ/mol) with increasing the coverage. The adsorption of CO₂ on graphene was thus categorized into physisorption, which was further supported by the binding energies of CO₂ in core-level spectra. The adsorption states of CO₂ on graphene were theoretically examined by means of the van der Waals density functional (vdW-DF) method that includes nonlocal correlation. The experimental desorption energy was successfully reproduced with high accuracy using vdW-DF calculations; the optB86b-vdW functional was found to be most appropriate to reproduce the desorption energy in the present system.