Dissociative adsorption of water at vacancy defects in graphite

被引:75
作者
Cabrera-Sanfelix, Pepa
Darling, George R.
机构
[1] Univ Liverpool, Dept Chem, Surface Sci Res Ctr, Liverpool L69 3BX, Merseyside, England
[2] DIPC, San Sebastian 20018, Spain
基金
英国工程与自然科学研究理事会;
关键词
D O I
10.1021/jp076241b
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We have performed density-functional calculations to investigate the adsorption of H2O on perfect and defected graphite (0001) represented by a single graphene sheet. On the perfect surface, the water physisorbs, as expected, with no significant preference for the adsorption site. At a vacancy site, the interaction is much more significant, with a computed binding energy of similar to 210 meV in a weak chemisorption/strong physisorption state. The H2O sits with one H pointing down to a carbon atom, which is pulled out of the plane by similar to 0.55 angstrom. From this physisorption state, dissociative chemisorption will occur after overcoming a barrier of 0.8-0.9 eV (similar to 0.6-0.7 eV relative to the gas-phase). The lowest dissociation barrier obtained is similar to 0.47 eV along a path largely avoiding the physisorption well. The dissociation paths have an intermediate step, in which the molecule partially dissociates to H and OH. Subsequently, the chemisorbed OH stretches, breaking into O and H atoms chemisorbed on separate C atoms on the vacancy with a total exothermicity of similar to 3.21 eV.
引用
收藏
页码:18258 / 18263
页数:6
相关论文
共 49 条
[11]   Sample manipulation in micro total analytical systems [J].
Greenwood, PA ;
Greenway, GM .
TRAC-TRENDS IN ANALYTICAL CHEMISTRY, 2002, 21 (11) :726-740
[12]   Vacancy and interstitial defects at graphite surfaces: Scanning tunneling microscopic study of the structure, electronic property, and yield for ion-induced defect creation [J].
Hahn, JR ;
Kang, H .
PHYSICAL REVIEW B, 1999, 60 (08) :6007-6017
[13]   Theoretical study of the adsorption of water on a model soot surface: I. Quantum chemical calculations [J].
Hamad, S ;
Mejias, JA ;
Lago, S ;
Picaud, S ;
Hoang, PNM .
JOURNAL OF PHYSICAL CHEMISTRY B, 2004, 108 (17) :5405-5409
[14]  
HANASAKI I, 2006, J CHEM PHYS, P124
[15]   The interaction of water with solid surfaces: fundamental aspects revisited [J].
Henderson, MA .
SURFACE SCIENCE REPORTS, 2002, 46 (1-8) :1-308
[16]   The effect of gas adsorption on the field emission mechanism of carbon nanotubes [J].
Kim, C ;
Choi, YS ;
Lee, SM ;
Park, JT ;
Kim, B ;
Lee, YH .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2002, 124 (33) :9906-9911
[17]   AB-INITIO MOLECULAR-DYNAMICS SIMULATION OF THE LIQUID-METAL AMORPHOUS-SEMICONDUCTOR TRANSITION IN GERMANIUM [J].
KRESSE, G ;
HAFNER, J .
PHYSICAL REVIEW B, 1994, 49 (20) :14251-14269
[18]   Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set [J].
Kresse, G ;
Furthmuller, J .
PHYSICAL REVIEW B, 1996, 54 (16) :11169-11186
[19]   ABINITIO MOLECULAR-DYNAMICS FOR LIQUID-METALS [J].
KRESSE, G ;
HAFNER, J .
PHYSICAL REVIEW B, 1993, 47 (01) :558-561
[20]   From ultrasoft pseudopotentials to the projector augmented-wave method [J].
Kresse, G ;
Joubert, D .
PHYSICAL REVIEW B, 1999, 59 (03) :1758-1775