Electrochemical-STM Analysis of Platinum-Complex Adstructures and Platinum Nanoparticles on Au(hkl) Electrode Surfaces for Oxygen Reduction Reaction

摘要

One of the major goals of surface science researches is to clarify atomic scale characteristics of the structures of electrode surfaces during reaction processes, since many electrochemical reactions on electrode surfaces are structure-sensitive. Correlational studies between surface structure and catalytic activity typically employ two approaches, the researches based on (1) single-crystal surfaces with steps and (2) nanoparticles supported on electrodes. The electrocatalytic properties of nanoparticles, especially Pt, have been studied to gain fundamental knowledge on the behavior of electrocatalysts. The development of Pt nanoparticles with appropriate activities, which is tailored as a function of parameters such as the structure of catalyst surfaces, the particle size and shape of the catalyst, and the nature of the substrate, is important for technological application of the electrocatalysts. We previously reported the electrodeposition of Pt from spontaneously adsorbed Pt complexes with various halide ligands on Au(111). However, the effect of substrate structures on adlayer formation and deposition of spontaneously adsorbed Pt complexes is still obscure, and a systematic investigation of the interplay of deposition conditions, Pt adlayer morphology, and electrocatalytic behavior of electro-reactions such as oxygen reduction reaction (ORR) is required.