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International Journal of Electrochemistry
Volume 2016, Article ID 2935035, 10 pages
http://dx.doi.org/10.1155/2016/2935035
Research Article

Dealloying Behavior of NiCo and NiCoCu Thin Films

Department of Physics, Hope College, Holland, MI 49423, USA

Received 29 July 2016; Accepted 22 September 2016

Academic Editor: Jiehua Liu

Copyright © 2016 Benjamin E. Peecher and Jennifer R. Hampton. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Porous metals and alloys, such as those fabricated via electrochemical dealloying, are of interest for a variety of energy applications, ranging from their potential for enhanced catalytic behavior to their use as high surface area supports for pseudocapacitor materials. Here, the electrochemical dealloying process was explored for electrodeposited binary NiCo and ternary NiCoCu thin films. For each of the four different metal ratios, films were dealloyed using linear sweep voltammetry to various potentials in order to gain insight into the evolution of the film over the course of the linear sweep. Electrochemical capacitance, scanning electron microscopy, and energy dispersive X-ray spectroscopy were used to examine the structure and composition of each sample before and after linear sweep voltammetry was performed. For NiCo films, dealloying resulted in almost no change in composition but did result in an increased capacitance, with greater increases occurring at higher linear sweep potentials, indicating the removal of material from the films. Dealloying also resulted in the appearance of large pores on the surface of the high nickel percentage NiCo films, while low nickel percentage NiCo films had little observable change in morphology. For NiCoCu films, Cu was almost completely removed at linear sweep potentials greater than 0.5 V versus Ag/AgCl. The linear sweep removed large Cu-rich dendrites from the films, while also causing increases in measured capacitance.