Kinetics analysis of Ni-TiO2 composite system during the initial stages of electrocrystallization
首发时间:2009-03-11
Abstract:The initial stage of Ni-TiO2 composite system electrodeposition on the electrochemically activated copper electrode from an acid solution of nickel sulfate was investigated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Analysis of current-time transients performed using the nonlinear fitting procedure.The influence of TiO2 particles was analyzed by comparing with the pure Ni system. The results showed that, in the case of low over potential (<-820mV vs.SCE), the codeposition of Ni-TiO2 system follows a Scharifker-Hills (SH) progressive nucleation/growth mechanism. While in the case of higher over potential (>-850mV vs.SCE), it meets a SH instantaneous nucleation/growth mechanism. In the Nyquist plots, the appearance of the characteristic inductive loops is at a lower over potential than that of pure nickel. The presence of the TiO2 particles, the nucleation potentials of Ni turn to positive direction ,the nucleation relaxation time tm was decreased clearly,and the charge transfer resistance was decreased.
keywords: Ni-TiO2 system electrocrystallization cyclic voltammetry electrochemical impedance spectroscopy
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Kinetics analysis of Ni-TiO2 composite system during the initial stages of electrocrystallization
摘要:The initial stage of Ni-TiO2 composite system electrodeposition on the electrochemically activated copper electrode from an acid solution of nickel sulfate was investigated using cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Analysis of current-time transients performed using the nonlinear fitting procedure.The influence of TiO2 particles was analyzed by comparing with the pure Ni system. The results showed that, in the case of low over potential (<-820mV vs.SCE), the codeposition of Ni-TiO2 system follows a Scharifker-Hills (SH) progressive nucleation/growth mechanism. While in the case of higher over potential (>-850mV vs.SCE), it meets a SH instantaneous nucleation/growth mechanism. In the Nyquist plots, the appearance of the characteristic inductive loops is at a lower over potential than that of pure nickel. The presence of the TiO2 particles, the nucleation potentials of Ni turn to positive direction ,the nucleation relaxation time tm was decreased clearly,and the charge transfer resistance was decreased.
关键词: Ni-TiO2 system; electrocrystallization; cyclic voltammetry; electrochemical impedance spectroscopy
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Kinetics analysis of Ni-TiO2 composite system during the initial stages of electrocrystallization
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