Acta Chim. Sinica ›› 2015, Vol. 73 ›› Issue (11): 1189-1195.

Article

内掺Sc原子的扩展三明治结构graphene-Sc-graphene的几何结构,电子性质和储氢性能研究

1. 河海大学理学院 南京 210098
• 投稿日期:2015-05-27 发布日期:2015-08-18
• 通讯作者: 唐春梅 E-mail:tcmnj@163.com
• 基金资助:

项目受中央高校基本科研业务专项资金资助(Grant No. 2015B19314)、江苏省“六大人才高峰”培养资助(Grant No. 2015-XCL-010)、国家自然科学基金(Grant No. 11104062)和江苏省青蓝工程资助.

Geometric Structure, Electronic Property, and Hydrogen Storage Capacity of the Sc Atoms Decorated Expanded Sandwich Type Structure Graphene-Sc-graphene

Tang Chunmei, Wu Jiaren, Wan Yimin, Zhang Zhengjun, Kang Jing, Xiang Yuanyuan, Zhu Weihua

1. College of Science, Hohai University, Nanjing 210098, China
• Received:2015-05-27 Published:2015-08-18
• Supported by:

Project supported by the Fundamental Research Funds for the Central Universities (Grant No. 2015B19314), Six talent peaks project in Jiangsu Province (Grant No. 2015-XCL-010), National Natural Science Foundation of China (Grant No. 11104062) and Qing Lan Project of Jiangsu province.

With the extensive use of fossil fuels such as coal and oil, the energy crisis and the accompanying environmental pollution has become a serious problem today, hydrogen has attracted widespread concern because of its less pollution and renewable usage. One of the key issues affecting the widespread use of hydrogen energy is the hydrogen storage. The metal decorated nanomaterials exhibited remarkable hydrogen adsorption capacities. The generalized gradient approximation based on density functional theory is used to study the geometric structure, electronic property, and hydrogen storage capacity of the Sc atom decorated expanded sandwich type structure graphene-Sc2-graphene. It is calculated that the structure with the Sc atom locating above the hollow site of the hexagonal ring on the graphene plane has the largest binging energy, but smaller than the experimental cohesive energy of bulk Sc (3.90 eV). However, when one or more Sc atoms locate between two graphene layers and about 2 Å distance to the substrate, the binding energy of the Sc atom to the substrate increase up to 5 eV, much larger than the experimental cohesive energy of bulk Sc (3.90 eV), so can prevent them from clustering on the graphene surface. Therefore, the sandwich type structure obviously increases the binding strength between the Sc atom and the substrate. It is known from the 18-electron rule that the structure can be stabilized through adsorbing the hydrogen molecules. Therefore, they can become the ideal hydrogen storage nanomaterials. Each Sc in the graphene-Sc-graphene sandwich type structure can adsorb up to two H2 molecules, and the average adsorption energy of H2 for graphene-(Sc-H2)-graphene and graphene-(Sc-2H2)-graphene are 0.67 eV and 0.54 eV respectively, which are between the physical adsorption and chemical adsorption (0.1～0.8 eV), therefore, they can realize the reversible adsorption of hydrogen. The expanded graphene-Sc-graphene sandwich type structure adsorbs hydrogen mainly through the Dewar-Kubas interaction and forms the π-δ-π electronic structure.