Platinum plays a central role in a variety of electrochemical devices and its practical use depends on the prevention of electrode degradation. However, understanding the underlying atomic processes under conditions of repeated oxidation and reduction inducing irreversible surface structure changes has proved challenging. Here, we examine the correlation between the evolution of the electrochemical signal of Pt(111) and its surface roughening by simultaneously performing cyclic voltammetry and in situ electrochemical scanning tunnelling microscopy (EC-STM). We identify a ‘nucleation and early growth’ regime of nanoisland formation, and a ‘late growth’ regime after island coalescence, which continues up to at least 170 cycles. The correlation analysis shows that each step site that is created in the ‘late growth’ regime contributes equally strongly to both the electrochemical and the roughness evolution. In contrast, in the ‘nucleation and early growth’ regime, created step sites contribute to the roughness, but not to the electrochemical signal.

铂在各种电化学装置中起着核心作用，其实际用途取决于防止电极降解。但是，在重复氧化和还原导致不可逆的表面结构变化的条件下，了解潜在的原子过程已证明具有挑战性。在这里，我们通过同时执行循环伏安法和原位电化学扫描隧道显微镜（EC-STM），检查Pt（111）电化学信号的演变与其表面粗糙之间的相关性。我们确定了纳米岛形成的“成核和早期生长”机制，以及岛聚结后的“晚期增长”机制，该机制持续至少170个周期。相关分析表明，在“后期生长”状态下创建的每个台阶部位均对电化学和粗糙度演变具有同等重要的作用。相反，在“成核和早期生长”状态下，产生的台阶部位会增加粗糙度，但不会增加电化学信号。