摘要： •The adsorption metanilic acid (MA) on Au(111) electrode surface was studied by in situ STM and XPS.•Bisulfate anions competed with MA for surface sites on Au(111) at positive potentials.•MA is oxidized at more positive potential than aniline.•Oxidation of MA did not yield polymeric molecules.•Polyaniline was produced on Au(111) in a mixed solution of MA and aniline. Oxidation of aniline and its derivatives can yield cationic radicals, which induce chain reactions to produce polymeric materials with notable conductivity. When these events occur on ordered electrode surface, admolecules can be adsorbed in some specific manner that guides reactions to proceed in some specific directions to yield products with well-defined conformations. This study employed cyclic voltammetry, X-ray photoemission spectroscopy (XPS), and in situ scanning tunneling microscopy (STM) to study the adsorption and polymerization of metanilic acid (MA) in 0.5MH2SO4. MA molecules were adsorbed in highly ordered adlattices characterized as Au(111) – (19×31) and (27×31) at 0.5 and 0.8V (vs. reversible hydrogen electrode). These adlattices were displaced by bisulfate anions at E>1.0V. MA molecules still could be oxidized to yield polymer molecules, which lacked a well-defined structure. By contrast, MA and aniline molecules could be coadsorbed in a highly ordered Au(111) – (4×23) structure at 0.8V in 0.5M H2SO4+30mM aniline+3mM MA, which led to anisotropic oxidative polymerization in the 〈121〉 directions of the Au(111) electrode surface. According to ex situ XPS results, the as-produced linear polymeric chains were mainly polyaniline (PAN), rather than copolymer of aniline and MA. The surface structure and polymerization of aniline and MA varied greatly with their molar ratios. No ordered adlayer was observed in solution containing equal amounts (30mM) of MA and aniline. 出版者： Elsevier B.V 出版日期： 2014-03-01 出處： Journal of electroanalytical chemistry (Lausanne, Switzerland), 2014-03, Vol.716, p.150-157 版權： 2013 Elsevier B.V. 識別號： ISSN: 1572-6657 識別號： EISSN: 1873-2569 識別號： DOI: 10.1016/j.jelechem.2013.10.003
