Treatment of Reticulated Vitreous Carbon by Dielectric Barrier Discharge Plasma for Electrodes Production

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Processo FAPESP: 07/03714-3

Processo FAPESP: 10/03148-0

This paper deals with the surface modification of reticulated vitreous carbon (RVC) by dielectric barrier discharge (DBD) for electrodes production. RVC samples were exposed to air-DBD plasma for 5.0 and 10.0 min. Following the treatment, the specimens were characterized by scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle measurements, and electrochemical analyses [cyclic voltammetry (CV)]. The SEM images show an alteration of the RVC surface morphology because of the surface etching during the DBD processing. This finding is in agreement with the enhanced specific electrochemical surface area of RVC electrodes, which is related to an increase of its surface roughness. In addition, a slight increase of the oxygen content on the surface was confirmed by XPS analysis. Therefore, the RVC surface became more hydrophilic as detected by water contact angle measurements. For corroborating this statement, a solid monolithic vitreous carbon was used for this test. An increase in the anodic charge of the RVC electrodes due to the surface oxidation was also observed. Raman spectra showed insignificant changes in the material crystalline structure.