Enhancement of CO2 adsorption on oxygen-functionalized epitaxial graphene surface under near-ambient conditions†,Physical Chemistry Chemical Physics

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Enhancement of CO2 adsorption on oxygen-functionalized epitaxial graphene surface under near-ambient conditions†
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2018-07-05 00:00:00 , DOI: 10.1039/c8cp03251c
Susumu Yamamoto _{1,

2,

3,

4} , Kaori Takeuchi _{1,

2,

3,

4} , Yuji Hamamoto _{4,

5,

6,

7,

8} , Ro-Ya Liu _{1,

2,

3,

4} , Yuichiro Shiozawa _{1,

2,

3,

4} , Takanori Koitaya _{1,

2,

3,

4} , Takashi Someya _{1,

2,

3,

4} , Keiichiro Tashima _{4,

9,

10,

11} , Hirokazu Fukidome _{4,

9,

10,

11} , Kozo Mukai _{1,

2,

3,

4} , Shinya Yoshimoto _{1,

2,

3,

4} , Maki Suemitsu _{4,

9,

10,

11} , Yoshitada Morikawa _{4,

5,

6,

7,

8} , Jun Yoshinobu _{1,

2,

3,

4} , Iwao Matsuda _{1,

2,

3,

4}

Affiliation

The functionalization of graphene is important in practical applications of graphene, such as in catalysts. However, the experimental study of the interactions of adsorbed molecules with functionalized graphene is difficult under ambient conditions at which catalysts are operated. Here, the adsorption of CO₂ on an oxygen-functionalized epitaxial graphene surface was studied under near-ambient conditions using ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). The oxygen-functionalization of graphene is achieved in situ by the photo-induced dissociation of CO₂ with X-rays on graphene in a CO₂ gas atmosphere. The oxygen species on the graphene surface is identified as the epoxy group by XPS binding energies and thermal stability. Under near-ambient conditions of 1.6 mbar CO₂ gas pressure and 175 K sample temperature, CO₂ molecules are not adsorbed on the pristine graphene, but are adsorbed on the oxygen-functionalized graphene surface. The increase in the adsorption energy of CO₂ on the oxygen-functionalized graphene surface is supported by first-principles calculations with the van der Waals density functional (vdW-DF) method. The adsorption of CO₂ on the oxygen-functionalized graphene surface is enhanced by both the electrostatic interactions between the CO₂ and the epoxy group and the vdW interactions between the CO₂ and graphene. The detailed understanding of the interaction between CO₂ and the oxygen-functionalized graphene surface obtained in this study may assist in developing guidelines for designing novel graphene-based catalysts.

中文翻译：

在接近环境的条件下增强氧官能化外延石墨烯表面上的CO ₂吸附†

石墨烯的官能化在石墨烯的实际应用中，例如在催化剂中是重要的。然而，在操作催化剂的环境条件下，很难对吸附分子与官能化石墨烯的相互作用进行实验研究。在此，使用环境压力X射线光电子能谱（AP-XPS）在接近环境的条件下研究了在氧官能化的外延石墨烯表面上的CO ₂吸附。石墨烯的氧官能实现原位由CO的光诱导解离₂与X射线在石墨烯上，在CO ₂气体气氛。通过XPS结合能和热稳定性将石墨烯表面上的氧种识别为环氧基。在1.6 mbar CO ₂气压和175 K样品温度的接近环境条件下，CO ₂分子不吸附在原始石墨烯上，而是吸附在氧官能化的石墨烯表面上。通过范德华密度泛函（vdW-DF）方法进行的第一性原理计算支持了氧官能化石墨烯表面上CO ₂吸附能的增加。CO的吸附₂氧-官能化石墨烯表面上由CO之间两个静电相互作用增强₂CO ₂和石墨烯之间的环氧基和vdW相互作用。这项研究中获得的对CO ₂和氧官能化石墨烯表面之间相互作用的详细理解可能有助于制定设计新颖的基于石墨烯的催化剂的指南。

更新日期：2018-07-05

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