Self-Terminated Electrodeposition of Ni, Co, and Fe Ultrathin Films

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• 作者：Rongyue Wang ; Ugo Bertocci ; Haiyan Tan ; Leonid A. Bendersky ; Thomas P. Moffat
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：July 28, 2016
• 年：2016
• 卷：120
• 期：29
• 页码：16228-16237
• 全文大小：566K
• 年卷期：0
• ISSN：1932-7455

文摘

Self-terminated Fe-group metal (Ni, Co, Fe) electrodeposition occurs at potentials negative of the onset of water reduction where OH^– generation leads to the formation of a blocking hydroxide monolayer. Quenching of metal deposition is accompanied by an increase in dissipative energy loss in microbalance experiments attributed to increased hydrogen bonding to the adjacent double layer. Pulse deposition at −1.5 V_SSCE in 5 mmol/L (NiCl₂, CoCl₂, FeSO₄) – 0.1 mol/L NaCl pH 3.0 electrolytes yields fully coalesced ultrathin films of Ni, Co, Fe, or alloys thereof, on Au. The film thickness is controlled by the nucleation, growth, and termination dynamics constrained by the electrochemical cell time constant. Precipitation of bulk Ni(OH)₂ and related phases is minimized by using short deposition times and dilute metal cation concentrations to limit supersaturation. The rapid deposition of smooth, compact ultrathin Fe, Co, and Ni films should facilitate mechanistic and durability studies of Fe-group metal catalysis and the fabrication of emerging microdevices.