Revealing the Multibonding State between Hydrogen and Graphene-Supported Ti Clusters
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- 作者：Keisuke Takahashi ; Shigehito Isobe ; Kengo Omori ; Torge Mashoff ; Domenica Convertino ; Vaidotas Miseikis ; Camilla Coletti ; Valentina Tozzini ; Stefan Heun
- 刊名：Journal of Physical Chemistry C
- 出版年：2016
- 出版时间：June 23, 2016
- 年：2016
- 卷：120
- 期：24
- 页码：12974-12979
- 全文大小：381K
- 年卷期：0
- ISSN：1932-7455
文摘
Hydrogen adsorption on graphene-supported metal clusters has brought much controversy due to the complex nature of the bonding between hydrogen and metal clusters. The bond types of hydrogen and graphene-supported Ti clusters are experimentally and theoretically investigated. Transmission electron microscopy shows that Ti clusters of nanometer size are formed on graphene. Thermal desorption spectroscopy captures three hydrogen desorption peaks from hydrogenated graphene-supported Ti clusters. First-principles calculations also found three types of interaction: two types of bonds with different partial ionic character and physisorption. The physical origin for this rests on the charge state of the Ti clusters: when Ti clusters are neutral, H2 is dissociated, and H forms bonds with the Ti cluster. On the contrary, H2 is adsorbed in molecular form on positively charged Ti clusters, resulting in physisorption. Thus, this work clarifies the bonding mechanisms of hydrogen on graphene-supported Ti clusters.