Deng Xin, Galli Federica, Koper Marc T M
Leiden Institute of Chemistry , Leiden University , PO Box 9502, 2300 RA , Leiden , The Netherlands.
Huygens-Kamerlingh Onnes Laboratory , Leiden University , Niels Bohrweg 2 , 2333 CA Leiden , The Netherlands.
J Am Chem Soc. 2018 Oct 17;140(41):13285-13291. doi: 10.1021/jacs.8b07452. Epub 2018 Oct 3.
Understanding the electrochemical behavior of Pt at the solid/liquid interface is of significant importance for the development of efficient electrochemical devices, such as fuel cells and water electrolyzers. In this work, the evolution of the surface morphology of a polycrystalline platinum under potential cycling conditions was investigated by in situ electrochemical atomic force microscopy (EC-AFM). After 50 cycles between 0.05 and 1.8 V in 0.1 M HSO, the Pt surface is coarsened and nanoparticles of several nanometers appear on the surface. The critical upper and lower potentials for the formation of nanoparticles are found to be 1.8 and 0.8 V, respectively. The in situ AFM observation coupled with Cyclic Voltammerty reveals the periodic disappearance and reappearance of the nanoparticles, based on which the formation of nanoparticles is attributed to the deposition of dissolved Pt from solution, and a model for the nanoparticle formation is proposed. While the formation of a thick oxide layer is a prerequisite, the reduction process is found to have a strong influence on Pt nanoparticle formation as well. This investigation provides a visualization of the Pt electrode surface under electrochemical control in a large potential window, enabling a broader understanding of the Pt electrode roughening mechanisms.
了解铂在固/液界面的电化学行为对于开发高效的电化学装置（如燃料电池和水电解槽）具有重要意义。在这项工作中，通过原位电化学原子力显微镜（EC-AFM）研究了多晶铂在电位循环条件下表面形貌的演变。在0.1 M HSO中于0.05至1.8 V之间循环50次后，铂表面变得粗糙，表面出现了几纳米的纳米颗粒。发现形成纳米颗粒的临界上限和下限电位分别为1.8 V和0.8 V。原位AFM观察与循环伏安法相结合揭示了纳米颗粒的周期性消失和重新出现，据此纳米颗粒的形成归因于溶液中溶解的铂的沉积，并提出了纳米颗粒形成的模型。虽然形成厚氧化层是一个先决条件，但发现还原过程对铂纳米颗粒的形成也有很大影响。这项研究提供了在大电位窗口下电化学控制下铂电极表面的可视化，有助于更广泛地理解铂电极粗糙化机制。
