The electrocatalytic influence of underpotential lead adsorbates on the reduction of nitrobenzene and nitrosobenzene on silver single crystal surfaces in methanolic solutions

✍ Scribed by G. Kokkinidis; K. Jüttner

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 657 KB
• Volume: 26
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(81)85065-7

✦ Synopsis

The electrocatalytic influence of underpotential lead adsorbates on the reduction of nitrobenzene (+N02)

and nitrosobenzene ($-NO) on poly-and monocrystalline silver electrodes was studied in methanolic solutions. On the bare, silver substrates &--NO, and #+-NO reduced to phenylhydroxylamine (ql-NHOH) in neutral solutions and to anilin (+NH2) in acid solutions. The underpotential deposition of lead on the silver substrates caused a partial inhibition of the +N02 and +NO reduction processes in acid solutions. The reduction of the intermediate @-NHOH to +NH2 was entirely inhibited by a complete coverage of the lead adsorbate. In the presence of Cl-ions in the electrolyte a pseudo-catalytic effect was found which is interpreted in terms of a competitive adsorption-desorption mechanism involving a replacement of specifically adsorbed chloride by the preferential adsorption of lead.