Behjati Saeid, Hajilo Mojtaba, Albers Maximilian, Koper Marc T M
Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, Leiden 2300 RA, The Netherlands.
Chemistry Department, Sharif University of Technology, P.O. Box 11155-3615, Tehran 19166, Iran.
J Phys Chem C Nanomater Interfaces. 2025 May 5;129(19):8915-8926. doi: 10.1021/acs.jpcc.5c01177. eCollection 2025 May 15.
This study investigates the inhomogeneous roughening of a Au(111) single-crystal electrode surface during oxidation-reduction cycles (ORCs) in a 0.1 M perchloric acid (HClO) solution using electrochemical scanning tunneling microscopy (EC-STM). The results reveal that, even in ultrapure HClO, the presence of minor impurities can lead to three distinguishable surface evolutions, on one and the same crystal: surface roughening by the formation of adatom and vacancy islands, gold dissolution resulting in vacancy island formation (in conjunction with step-line recession), and the surface remaining intact even during oxidation-reduction cycling. The impact of trace impurities, specifically sulfate (SO ) and chloride (Cl), on the surface structure development is investigated by adding 10 μM of HSO and HCl to the HClO solution. Our results reveal that sulfate significantly promotes uniform roughening, while chloride accelerates gold dissolution and step-line recession. These findings highlight the critical role of minor impurities in altering the electrochemical behavior of gold surfaces and how sensitive the local evolution of the surface structure is to these effects.
本研究利用电化学扫描隧道显微镜（EC-STM），研究了在0.1M高氯酸（HClO）溶液中进行氧化还原循环（ORC）时，Au(111)单晶电极表面的不均匀粗糙化现象。结果表明，即使在超纯HClO中，微量杂质的存在也会导致同一晶体上出现三种可区分的表面演变：通过形成吸附原子和空位岛使表面粗糙化、金溶解导致空位岛形成（与台阶线后退同时发生），以及即使在氧化还原循环过程中表面仍保持完整。通过向HClO溶液中添加10μM的HSO和HCl，研究了痕量杂质，特别是硫酸盐（SO）和氯化物（Cl）对表面结构发展的影响。我们的结果表明，硫酸盐显著促进均匀粗糙化，而氯化物加速金溶解和台阶线后退。这些发现突出了微量杂质在改变金表面电化学行为中的关键作用，以及表面结构的局部演变对这些影响的敏感程度。
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