화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.161, No.9, H583-H592, 2014
Electrocatalysis of Hypophosphite on Nickel Investigated Using Time Resolved Fourier Transform Electrochemical Impedance Spectroscopy
Electro-oxidation of hypophosphite plays an important role in the electro-less deposition of Ni used to fabricate surface engineered films, alloys, and coatings for a variety of applications. At the same time, the kinetic details of this oxidation reaction comprise an ideal framework for studying many general mechanistic aspects of electrocatalysis on transition metal substrates. The present work utilizes these specific attributes of hypophosphite oxidation to probe the underlying function of the incipient hydrous oxide of Ni in promoting the catalytic properties of this metal in an alkaline medium. The experiments reported here use time-resolved Fourier-transform electrochemical impedance spectroscopy (FT-EIS), strategically coupled with scan-rate controlled voltammetry. The results suggest that the incipient hydrous oxide Ni(OH)(ad) formed at the onset of hypophosphite oxidation catalytically promotes the latter's precursor de-hydrogenation step. While voltammetry provides suggestive evidence for these Ni(OH)(ad) induced effects, the FT-EIS data serve to gather more direct signatures of the catalytic function of Ni(OH)(ad). (C) 2014 The Electrochemical Society. All rights reserved.