Effects of Adsorbed Polyaniline on Redox Processes on As2O3 Surfaces

✍ Scribed by Robson F. de Farias; Jucimar M. de Souza; Jailson V. de Melo; Claudio Airoldi

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 98 KB
• Volume: 227
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.2000.6826

✦ Synopsis

Polyaniline deposited on As

2 O 3 surface resulted in a new material, which was characterized by infrared spectoscopy, thermogravimetry, differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and cyclic voltammetry. The mass percentage of polymer deposited on oxide surface is approximately 13%. The scanning electron microscopy images as well as the X-ray diffraction patterns provided conclusive evidence that the oxide surface is coated by the polymer. The cyclic voltammograms of the polyaniline adsorbed on As 2 O 3 surface showed that the adsorbate exerts remarkable effects on redox processes on this oxide. The pure oxide exhibited two oxidation/reduction peaks at 0.25/-0.06 and 0.47/-0.25 V attributed tentatively to the processes As 2 O 3 (s) + 6H + + 6e -= 2As(s) + 3H 2 O and As(s) + 3H + + 3e -= AsH 3 (g), respectively. The polyaniline-coated sample exhibited a better-defined voltammogram in which the first oxidation peak of the oxide had its intensity increased about four times.