Electrochemical evidence of the adsorption of alkanethiols on two sites on Ag(111)

被引:49
作者
Mohtat, N [1 ]
Byloos, M [1 ]
Soucy, M [1 ]
Morin, S [1 ]
Morin, M [1 ]
机构
[1] Univ Ottawa, Dept Chem, Ottawa, ON K1N 6N5, Canada
来源
JOURNAL OF ELECTROANALYTICAL CHEMISTRY | 2000年 / 484卷 / 02期
基金
加拿大自然科学与工程研究理事会;
关键词
thiols; Ag(111) single crystal; reduction; chronoamperometry; cyclic voltammetry; FTIR spectroscopy;
D O I
10.1016/S0022-0728(00)00063-2
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
We present spectroscopic and electrochemical results consistent with the adsorption of alkanethiols on two sites and the formation of a very densely packed, stable, monolayer on Ag(111). A surface coverage of alkanethiols of 8.5 (+/- 0.4) x 10(-10) mol cm(-2) was calculated from the charge associated with the reduction of a monolayer of alkanethiols. Alkanethiol modified Ag(111) cm electrodes were found to have lower capacitances than the alkanethiol modified Au(111) electrodes. The lower capacitances are due to the higher surface concentration of alkanethiols on Ag(111). The very low intensity of the methylene CH stretching bands of alkanethiols with alkane chains of four to nine carbons chemisorbed on Ag(111) suggests a vertical orientation of all-trans alkane chains. No vibrational evidence of oxidation of the chemisorbed alkanethiols was found after exposure to air for up to 6 weeks. A fine structure consisting of two current peaks was observed in all cyclic voltammograms of the reduction of chemisorbed alkanethiols. This revealed that the reduction of chemisorbed alkanethiols occurs in two steps on Ag(111). Chronoamperometric measurements also support a two-step reductive desorption of alkanethiols. The high surface concentration of alkanethiols and the orientation of the alkane chains suggest that the fine structure in the voltammograms is due to the reduction of the alkanethiols from two adsorption sites. (C) 2000 Elsevier Science S.A. All rights reserved.
引用
收藏
页码:120 / 130
页数:11
相关论文
共 53 条
[1]   Kinetics of formation of long-chain n-alkanethiolate monolayers on polycrystalline gold [J].
Bensebaa, F ;
Voicu, R ;
Huron, L ;
Ellis, TH ;
Kruus, E .
LANGMUIR, 1997, 13 (20) :5335-5340
[2]   SURFACE RAMAN-SCATTERING OF SELF-ASSEMBLED MONOLAYERS FORMED FROM 1-ALKANETHIOLS - BEHAVIOR OF FILMS AT AU AND COMPARISON TO FILMS AT AG [J].
BRYANT, MA ;
PEMBERTON, JE .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1991, 113 (22) :8284-8293
[3]   Formation of a self-assembled monolayer via the electrospreading of physisorbed micelles of thiolates [J].
Byloos, M ;
Al-Maznai, H ;
Morin, M .
JOURNAL OF PHYSICAL CHEMISTRY B, 1999, 103 (31) :6554-6561
[4]   SUBSTRATE DEPENDENCE OF THE SURFACE-STRUCTURE AND CHAIN PACKING OF DOCOSYL MERCAPTAN SELF-ASSEMBLED ON THE (111), (110), AND (100) FACES OF SINGLE-CRYSTAL GOLD [J].
CAMILLONE, N ;
CHIDSEY, CED ;
LIU, G ;
SCOLES, G .
JOURNAL OF CHEMICAL PHYSICS, 1993, 98 (05) :4234-4245
[5]   STRUCTURES OF SELF-ASSEMBLED MONOLAYERS OF AROMATIC-DERIVATIZED THIOLS ON EVAPORATED GOLD AND SILVER SURFACES - IMPLICATION ON PACKING MECHANISM [J].
CHANG, SC ;
CHAO, I ;
TAO, YT .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1994, 116 (15) :6792-6805
[6]   CHARACTERIZATION OF EXTREMELY LOW DEFECT DENSITY HEXADECANETHIOL MONOLAYERS ON HG SURFACES [J].
DEMOZ, A ;
HARRISON, DJ .
LANGMUIR, 1993, 9 (04) :1046-1050
[7]   STRUCTURE OF SELF-ASSEMBLED DECANETHIOL ON AG(111) - A MOLECULAR RESOLUTION SCANNING-TUNNELING-MICROSCOPY STUDY [J].
DHIRANI, A ;
HINES, MA ;
FISHER, AJ ;
ISMAIL, O ;
GUYOTSIONNEST, P .
LANGMUIR, 1995, 11 (07) :2609-2614
[8]   SYNTHESIS, STRUCTURE, AND PROPERTIES OF MODEL ORGANIC-SURFACES [J].
DUBOIS, LH ;
NUZZO, RG .
ANNUAL REVIEW OF PHYSICAL CHEMISTRY, 1992, 43 :437-463
[9]   STRUCTURE OF CH3(CH2)17SH SELF-ASSEMBLED ON THE AG(111) SURFACE - AN INCOMMENSURATE MONOLAYER [J].
FENTER, P ;
EISENBERGER, P ;
LI, J ;
CAMILLONE, N ;
BERNASEK, S ;
SCOLES, G ;
RAMANARAYANAN, TA ;
LIANG, KS .
LANGMUIR, 1991, 7 (10) :2013-2016
[10]   INFRARED STUDY OF ADSORBED MOLECULES ON METAL SURFACES BY REFLECTION TECHNIQUES [J].
GREENLER, RG .
JOURNAL OF CHEMICAL PHYSICS, 1966, 44 (01) :310-&