Electrodeposition of copper on a Pt(111) electrode in sulfuric acid containing poly(ethylene glycol) and chloride ions as probed by in situ STM

Yunlin Fu, Te Pao, Sih Zih Chen, Shuehlin Yau, Wei Ping Dow, Yuh-Lang Lee

研究成果: Article同行評審

8 引文 斯高帕斯(Scopus)

摘要

This study employed real-time in situ STM imaging to examine the adsorption of PEG molecules on Pt(111) modified by a monolayer of copper adatoms and the subsequent bulk Cu deposition in 1 M H 2SO 4 + 1 mM CuSO 4+ 1 mM KCl + 88 μM PEG. At the end of Cu underpotential deposition (∼0.35 V vs Ag/AgCl), a highly ordered Pt(111)-(√3 × √7)-Cu + HSO 4 - structure was observed in 1 M H 2SO 4 + 1 mM CuSO 4. This adlattice restructured upon the introduction of poly(ethylene glycol) (PEG, molecular weight 200) and chloride anions. At the onset potential for bulk Cu deposition (∼0 V), a Pt(111)-(√3 × √3)R30°-Cu + Cl - structure was imaged with a tunneling current of 0.5 nA and a bias voltage of 100 mV. Lowering the tunneling current to 0.2 nA yielded a (4 × 4) structure, presumably because of adsorbed PEG200 molecules. The subsequent nucleation and deposition processes of Cu in solution containing PEG and Cl - were examined, revealing the nucleation of 2- to 3-nm-wide CuCl clusters on an atomically smooth Pt(111) surface at overpotentials of less than 50 mV. With larger overpotential (η > 150 mV), Cu deposition seemed to bypass the production of CuCl species, leading to layered Cu deposition, starting preferentially at step defects, followed by lateral growth to cover the entire Pt electrode surface. These processes were observed with both PEG200 and 4000, although the former tended to produce more CuCl nanoclusters. Raising [H 2SO 4] to 1 M substantiates the suppressing effect of PEG on Cu deposition. This STM study provided atomic- or molecular-level insight into the effect of PEG additives on the deposition of Cu.

原文English
頁(從 - 到)10120-10127
頁數8
期刊Langmuir
28
發行號26
DOIs
出版狀態Published - 2012 七月 3

All Science Journal Classification (ASJC) codes

  • 材料科學(全部)
  • 凝聚態物理學
  • 表面和介面
  • 光譜
  • 電化學

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