The electrochemistry of gold: II the electrocatalytic behaviour of the metal in aqueous media
The electrochemistry of gold: II the electrocatalytic behaviour of the metal in aqueous media
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DOI：
10.1007/bf03214760
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发表时间：
1998-01-01
期刊：
影响因子：
2.2
通讯作者：
Nugent, PF
中科院分区：
文献类型：
--
作者：
Burke, LD;Nugent, PF
尽管金是最贵重且最惰性的金属，并且是一种非常弱的化学吸附剂，但它却展现出非常广泛的电催化活性——尤其是在碱性环境中。这种出乎意料的行为在此根据纳米团簇、微粒或量子点的特殊性质得以合理的解释。这些作为金属表面缺陷存在的物种，在一个被称为预单层氧化的过程中，会在异常低的电位下（明显低于块状金的电位）发生氧化。由此产生的低覆盖度（或初期的）氧化物被认为是氧化反应的媒介，而在较低电位下存在的未氧化的活性金原子通常作为还原反应的媒介。贵金属的电催化作用常常局限于双电层区域，并且只有活性位点上的低覆盖度金属原子参与其中。金在碱性环境中活性的增强很容易根据超能斯特E/pH效应来解释。金属纳米团簇的特殊性质也可用于解释Haruta及其同事最近所报道的氧化物负载的金微粒令人惊讶的高催化活性水平。
Although it is the noblest and most inert of metals, and is a very: weak chemisorber, gold displays a very wide range of electrocatalytic activity - especially in base. Such unexpected behaviour is rationalized here in terms of the unusual properties of nanocluster, microparticles or quantum dots. Such species, present as defects at the metal surface, undergo oxidation at unusually low potentials (significantly lower than that of bulk gold) in a process known as premonolayer oxidation. The resulting low coverage (or incipient) oxide species are assumed to be the mediators for oxidation reactions while unoxidized active gold atoms, present at lower potentials, often act as the mediators for reduction. Electrocatalysis on noble metals is quite often confined to the double layer region and only low coverage metal atoms at active sites are involved. The enhanced activity of gold in base is readily rationalized in terms of a super-Nernstian E/pH effect. The unusual properties of metal nanoclusters may also be used to rationalize the surprisingly high level of catalytic activity of oxide-supported gold microparticles as reported recently by Haruta and co-workers.