单缺陷对Sc,Ti,V修饰石墨烯的结构及储氢性能的影响  

Effect of monovacancy on stability and hydrogen storage property of Sc/Ti/V-decorated graphene

作　　者：马丽娟[1] 韩婷 高升启 贾建峰[1] 武海顺[1] Ma Li-Juan;Han Ting;Gao Sheng-Qi;Jia Jian-Feng;Wu Hai-Shun(Key Laboratory of Magnetic Molecules&Magnetic Information Materials Ministry of Education,School of Chemical and Material Science,Shanxi Normal University,Linfen 041004,China)

机构地区：[1]山西师范大学化学与材料科学学院,磁性分子与磁信息材料教育部重点实验室,临汾041000

出　　处：《物理学报》2021年第21期391-400,共10页Acta Physica Sinica

基　　金：国家自然科学基金青年科学基金(批准号:21805176);山西省青年科技研究基金(批准号:201901D211394);山西师范大学校级创新项目(批准号:2020XSY030,2020XSY002)资助的课题。

摘　　要：寻找稳定高效的储氢材料是实现氢经济的关键.过渡金属修饰石墨烯储氢材料在理论上被广泛研究,但存在H2解离和金属团聚的问题.本文基于密度泛函理论对Sc,Ti,V修饰单缺陷石墨烯的结构及储氢性能进行计算.结果表明:单缺陷使Sc,Ti,V与石墨烯的结合能提高4—5倍;Sc,Ti,V离子特性增强,可以通过静电相互作用吸附7,3和4个分子形式的氢;平均氢分子吸附能分别为–0.13,–0.20和–0.18 e V,处于室温和中等压力下储氢的最佳能量范围.而Sc,Ti,V修饰的完整石墨烯上第1个氢解离吸附,氢分子吸附能分别为–1.34,–1.34和–1.16 e V.特别重要的是,Sc,V修饰的缺陷石墨烯吸附和脱附氢分子过程中重构能仅为0.00 e V和0.03 e V,对实现快速吸放氢气非常有利.本研究将有利于深入认识3d过渡金属修饰碳材料的储氢机理.With the depletion of fossil fuels and the environmental problems,the development and utilization of new energy resources is imminent.Hydrogen energy is one of the main new energy sources in the 21st century.Finding stable and efficient hydrogen storage materials is the key to achieving the hydrogen economy.Transition metal(TM)-decorated graphenes have been widely studied as hydrogen storage materials theoretically,but they suffer metal agglomeration and H2 dissociation.Our calculations show that the reconstruction energy of Sc,Ti,V decorated pristine graphenes in the process of adsorption and desorption of hydrogen molecules are only 0.00,0.12 and 0.08 eV,respectively.The adsorption energy values of the first H2 dissociation adsorption on the Sc,Ti,V decorated pristine graphenes are–1.34,–1.34,and–1.16 eV,respectively.So,some hydrogen molecules are difficult to desorb at room temperature and medium pressure.In this paper,the stability and hydrogen storage properties of Sc,Ti,V decorated monovacancy graphene are also investigated based on density functional theory.The results show that the binding energy values between Sc,Ti,V and themonovacancy graphene are–6.93,–8.82,–9.30 eV,respectively,which indicate monovacancy can effectively avoid metal aggregation.The Sc,Ti and V atoms decorated on the monovacancy graphene would transfer more electrons to the carbon material with charge of+1.24|e|–+1.37|e|.They can adsorb 7,3 and 4 hydrogen molecules through electrostatic interaction.When a monovacancy is introduced,all of the hydrogen molecules are adsorbed in molecular form.The average adsorption energy values of H_(2) are–0.13,–0.20 and–0.18 eV,respectively,which are in the best energy range for the adsorption/desorption process at room temperature and medium pressure.The most important thing is that their deformations in the adsorption/desorption process are very small,which is conducive to the rapid hydrogen adsorption/desorption.The calculated results show that the monovacancy introduction can e

关 键 词：储氢 缺陷石墨烯 过渡金属 密度泛函理论 

分 类 号：TQ127.11[化学工程—无机化工] TB34[一般工业技术—材料科学与工程]