Investigation of electro-oxidation of methanol and benzyl alcohol at boron-doped diamond electrode: evidence for the mechanism for fouling film formation.
Boron-doped diamond (BDD) and glassy carbon (GC) electrodes are compared for electrochemical oxidation of methanol and benzyl alcohol. Cyclic voltammograms reveal that BDD electrode produces good oxidation signals for both methanol and benzyl alcohol, while GC produces no significant oxidation signal for either methanol or benzyl alcohol. Amperometric measurement of oxidation of methanol and benzyl alcohol on BDD shows development of a fouling film for benzyl alcohol but not for methanol. Prolonged (24 h) polarization of the BDD electrode at +2.0 V in benzyl alcohol generated enough fouling film for investigation by AFM, SEM, Raman, and FTIR techniques. AFM and SEM microscopy images confirm a fouling film confined to the low-lying regions of the polycrystallite BDD surface, indicating that the active sites of benzyl alcohol oxidation are located within these low-lying regions. The fouling material generated in the process of benzyl alcohol oxidation was identified from Raman and FTIR spectroscopy as polyester. Experiments confirm the fouling film can be removed and the electrode surface reactivated by brief polarization at +3.0 V. Amperometric results of concentration dependence confirm the BDD electrode is well suited for quantitative analysis applications of methanol and benzyl alcohol, with recognizable oxidation currents at micromolar concentration levels.
Chang
Chia-Chin
CC
Department of Environment and Energy and Department of Nature Science Education, National University of Tainan, Tainan, Taiwan 701. ccchang@mail.nutn.edu.tw
Chen
Li-Chia
LC
Liu
Shyh-Jiun
SJ
Chang
Hsien-Chang
HC
D000438:Alcohols; D019905:Benzyl Alcohol / Q000737:chemistry; D001895:Boron / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002627:Chemistry, Physical / Q000379:methods*; D018130:Diamond; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D000432:Methanol / Q000737:chemistry; D018625:Microscopy, Atomic Force; D008956:Models, Chemical; D010100:Oxygen / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013997:Time Factors
D000438:Alcohols; D002244:Carbon; D018130:Diamond; D019905:Benzyl Alcohol; D001895:Boron; D010100:Oxygen; D000432:Methanol