Structure of Au(111) and Au(100) single-crystal electrode surfaces at various potentials in sulfuric acid solution determined by in situ surface X-ray scattering

X線散乱法を用いた硫酸中におけるAu(111), Au(100)単結晶電極表面の構造解析

近藤 敏啓*; 森田 潤*; 花岡 一哉*; 高草木 達*; 田村 和久   ; 高橋 正光; 水木 純一郎; 魚崎 浩平*

Kondo, Toshihiro*; Morita, Jun*; Hanaoka, Kazuya*; Takakusagi, Satoru*; Tamura, Kazuhisa; Takahashi, Masamitsu; Mizuki, Junichiro; Uosaki, Kohei*

50mM硫酸水溶液中でのAu(111)及びAu(100)単結晶電極の表面構造の電極電位依存性について、表面X線散乱法を用いて検討した。Au(111), Au(100)面ともに、酸素吸着したまま、表面再配列が起きていることが明らかになった。

Potential-dependent surface structures of Au(111) and Au(100) single-crystal electrodes in a 50 mM HSO solution were investigated at an atomic level using in situ surface X-ray scattering (SXS) techniques. It was confirmed that both the Au(111) and Au(100) surfaces were reconstructed with an attached submonolayer of an oxygen species, most probably water, at 0 V (vs Ag/AgCl). Results at +0.95 V supported a previously suggested model for both the Au(111) and the Au(100) electrodes that, based on infrared and scanning tunneling microscopy measurements, the surfaces were a (11) structure with the coadsorbed sulfate anion and hydronium cation (HO). At +1.05 V, where a small amount of an anodic current flowed, adsorption of a monolayer of oxygen species was observed on both surfaces.