Substituent effects on the electrocatalytic reduction of oxygen on quinone-modified glassy carbon electrodes
作者:Fakhradin Mirkhalaf、Kaido Tammeveski、David J. Schiffrin
DOI:10.1039/b315963a
日期:——
The reduction of oxygen catalysed by two sulfur-containing derivatives of anthraquinone has been investigated. The quinones were chemically grafted to a glassy carbon electrode surface and the oxygen reduction reaction in alkaline solution followed a two-electron pathway yielding hydrogen peroxide. The mechanism proposed corresponds to an electrochemical–chemical (EC) reaction where the semiquinone radical anion electrochemically formed reacts chemically with oxygen. The influence on reactivity of electron withdrawing groups present in the quinone molecules has been studied and it is shown that there is an unexpected small dependence between reactivity and standard potential of the grafted quinones. It is shown that steric effects appear important in determining their electrocatalytic properties.
我们研究了蒽醌的两种含硫衍生物催化的氧气还原反应。醌类化合物被化学接枝到玻璃碳电极表面,碱性溶液中的氧还原反应遵循双电子途径,生成过氧化氢。提出的机理与电化学-化学(EC)反应相对应,即电化学形成的半醌基阴离子与氧气发生化学反应。研究了醌分子中存在的取电子基团对反应活性的影响,结果表明,反应活性与接枝醌的标准电位之间存在意想不到的微小依赖关系。研究结果表明,立体效应在决定醌类化合物的电催化特性方面起着重要作用。