Baranton Stève, Bélanger Daniel
Département de Chimie, Université du Québec à Montréal, Case Postale 8888, succursale Centre-Ville, Montréal, Québec, Canada H3C 3P8.
J Phys Chem B. 2005 Dec 29;109(51):24401-10. doi: 10.1021/jp054513+.
The derivatization of a glassy carbon electrode surface was achieved by electrochemical reduction of several in situ generated diazonium cations. The diazonium cations were synthesized in the electrochemical cell by reaction of the corresponding amines with NaNO2 in aqueous HCl. The versatility of the method was demonstrated by using six diazonium cations. This deposition method, which involves simple reagents and does not require the isolation and purification of the diazonium salt, enabled the grafting of covalently bounded layers which exhibited properties very similar to those of layers obtained by the classical derivatization method involving isolated diazonium salt dissolved in acetonitrile or aqueous acid solution. Cyclic voltammetry and electrochemical impedance spectroscopy carried out in aqueous solutions containing electroactive redox probe molecules such as Fe(CN)6(3-/4-) and Ru(NH3)6(3+) confirmed the barrier properties of the deposited layers. The chemical composition of the grafted layers was determined by X-ray photoelectron spectroscopy and surface coverage in the range 3 x 10(-10) to 6 x 10(-10) mol cm(-2) was estimated for films grown in our experimental conditions.
通过对几种原位生成的重氮阳离子进行电化学还原，实现了玻碳电极表面的衍生化。重氮阳离子是在电化学池中由相应的胺与盐酸中的亚硝酸钠反应合成的。使用六种重氮阳离子证明了该方法的通用性。这种沉积方法涉及简单的试剂，不需要分离和纯化重氮盐，能够接枝共价键合层，其性质与通过涉及溶解在乙腈或酸性水溶液中的分离重氮盐的经典衍生化方法获得的层非常相似。在含有电活性氧化还原探针分子（如铁氰化钾（Fe(CN)6(3-/4-)）和六氨合钌（Ru(NH3)6(3+)）的水溶液中进行的循环伏安法和电化学阻抗谱证实了沉积层的阻隔性能。通过X射线光电子能谱确定了接枝层的化学成分，并估计了在我们的实验条件下生长的薄膜的表面覆盖率在3×10(-10)至6×10(-10) mol cm(-2)范围内。
