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Nonlinear Self‐Organizing Kinetics in the Electrochemical Growth of Alumina Nanotube Arrays
Author(s) -
Fan Xing,
Liao Longfa,
Chang Yu,
Liu Zuohua,
Du Jun,
Tao Changyuan
Publication year - 2014
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201400010
Subject(s) - hydroxide , electrosynthesis , electrochemistry , dissolution , materials science , chemical physics , chemical engineering , diffusion , nanotechnology , chemistry , inorganic chemistry , electrode , thermodynamics , engineering , physics
The nonlinear self‐organizing kinetics that occur during the electrosynthesis of porous anodic alumina (PAA) are investigated. It is first found that the ordered PAA nanoarray forms through the self‐organization of aluminum hydroxide colloids, rather than the traditional pitting‐corrosion mechanism. There is more than one parallel reaction path in the system, and a nonlinear feedback mechanism exists in one of them. Both the spatial periodicity of the nanoarray and the time periodicity of the current are dominated by a nonlinear reaction path during the self‐organization of the diffusion–reaction coupled system. The electrochemical growth mechanism is analyzed and dynamic Equations are established. The self‐catalysis effect of the condensed cationic intermediates on the hydrolysis and condensation of Al hydroxide is explained. This widely exists in the electro‐dissolution of various metals and plays a key role in electrochemical oscillation or self‐organization when the system is driven far from its equilibrium state by the electric field. The slow diffusion of the condensed cations in the gel is key for the formation of the nanoarrays, which provides new ideas for structure control during the synthesis of ordered nano‐oxides.