Adsorption competition effects in the electrocatalytic reduction of organic halides on silver

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Vol. 532; no. 1; pp. 285 - 293
• Main Authors: Ardizzone, Silvia, Cappelletti, Giuseppe, Mussini, Patrizia Romana, Rondinini, Sandra, Doubova, Lioudmila M
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 06.09.2002; Elsevier Science
• Subjects: Adsorption competition; Chemistry; Electrochemistry; Exact sciences and technology; General and physical chemistry; Halide anions; Kinetics and mechanism of reactions; Organic electrocatalysis; Organic halides; Silver; Specific adsorption; Adsorption competition; Silver; Halide anions; Specific adsorption; Organic halides; Organic electrocatalysis; Electrode adsorption; Catalytic reaction; Aliphatic compound; Transition metal; Experimental study; Chemical reduction; Cyclic voltammetry; Electrocatalysis; Halogenated hydrocarbon; Electrode reaction; Crystal electrode; Reaction mechanism; Benzenic compound; Electrochemical reaction; Catalyst activity
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/S0022-0728(02)00950-6

A systematic study of {silver ∣ inorganic and/or organic halide} interphases is described, based on cyclovoltammetric and impedance experiments carried out on polycrystalline electrodes of high reproducibility (controlled by comparison with monocrystalline ones), in water and in acetonitrile. The adsorption competition is brought into focus (i) between the three inorganic halides Cl −, Br −, and I −, with the possible interference of ions from the supporting electrolyte, and (ii) between organic and inorganic halides, especially iodides. Actually adsorption competition proves to be a determining factor in the electrocatalytic mechanism (a remarkable threshold effect being observed for the reduction potentials of organic bromides in correspondence with the limiting negative potential for iodide anion adsorption). Vice versa, the variation of the reduction potentials of a given reacting molecule with the background electrolyte provides significant clues on the nature of the specifically adsorbed species.