New experimental evidence on the formation of platinum superactive sites in an electrochemical environment

被引：17

作者：

Diaz, V. ^{[3
]}

Real, S. ^{[1
]}

Teliz, E. ^{[2
]}

Zinola, C. F. ^{[2
]}

Martins, M. E. ^{[1
]}

机构：

[1] Natl Univ La Plata, Inst Invest Fisicoquim Teor & Aplicadas, RA-1900 La Plata, Argentina

[2] Univ Republica, Sch Sci, Fundamental Electrochem Lab, Montevideo 11400, Uruguay

[3] Univ Republica, Sch Engn, Inst Chem Engn, Montevideo 11300, Uruguay

来源：

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY | 2009年 / 34卷 / 08期

关键词：

Platinum; Superactive state; Triangularly modulated triangular potential sweep voltammetry; Electrochemical impedance; XPS; METHANOL OXIDATION ELECTROCATALYSIS; CONCENTRATED PHOSPHORIC-ACID; AQUEOUS-MEDIA; ELECTRODES; ELECTROOXIDATION; SURFACE; BEHAVIOR; RU; SPECTROSCOPY; POLARIZATION;

D O I：

10.1016/j.ijhydene.2009.02.008

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

New electrochemical results are found after the application of a constant cathodic polarization to the platinum/aqueous acid solution interface within the hydrogen evolution region. Voltammograms reveal highly stable anodic peaks emerging in the double-layer region assigned to the so-called "superactive" states. The severe cathodization produces the disruption of the platinum/aqueous solution interface leading to an open outer layer composed of metallic species highly coordinated to the solvent. These active sites are related with electrocatalytic features since the onset potential for water discharge is diminished. Voltammetry and modulated voltammetry explain the fact that platinum species highly coordinated to the solvent can be more oxidized since the reduction potential shifts toward more negative values. The alkalinization of the interface and the formation of new surface oxides in a different potential range are proposed. The latter produces electrocatalytic effects on methanol electrooxidation. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

引用

页码：3519 / 3530

页数：12

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