abstract
In this study, nanostructured ceria (CeO2) films are deposited on Si(100) and ITO coated glass substrates by pulsed DC magnetron sputtering using a CeO2 target. The influence on the films of using various gas ambients, such as a high purity Ar and a gas mixture of high purity Ar and O-2, in the sputtering chamber during deposition are studied. The film compositions are studied using XPS and SIMS. These spectra show a phase transition from cubic CeO2 to hexagonal Ce2O3 due to the sputtering process. This is related to the transformation of Ce4+ to Ce3+ and indicates a chemically reduced state of CeO2 due to the formation of oxygen vacancies. TGA and electrochemical cyclic voltammetry (CV) studies show that films deposited in an Ar atmosphere have a higher oxygen storage capacity (OSC) compared to films deposited in the presence of O-2. CV results specifically show a linear variation with scan rate of the anodic peak currents for both films and the double layer capacitance values for films deposited in Ar/O-2 mixed and Ar atmosphere are (1.6 +/- 0.2) x 10(-4) F and (4.3 +/- 0.5) x 10(-4) F, respectively. Also, TGA data shows that Ar sputtered samples have a tendency to greater oxygen losses upon reduction compared to the films sputtered in an Ar/O-2 mixed atmosphere. (C) 2015 Elsevier B.V. All rights reserved.
keywords
OXIDE THIN-FILMS; CHARGE STORAGE; ELECTROCATALYTIC ACTIVITY; MIXED OXIDES; CEO2; GROWTH; SPECTROSCOPY; CONDUCTIVITY; STABILITY; CATALYSTS
subject category
Chemistry; Electrochemistry; Energy & Fuels; Materials Science
authors
Eltayeb, A; Vijayaraghavan, RK; McCoy, A; Venkatanarayanan, A; Yaremchenko, AA; Surendran, R; McGlynn, E; Daniels, S
our authors
Aleksey Yaremchenko
Principal Researcher
Rajesh Surendran Nair
Post-doc Fellowshipacknowledgements
A. Eltayeb, S. Daniels and E. McGlynn specifically gratefully acknowledge postgraduate funding from INSPIRE, supported under the framework of the Irish government's PRTLI cycle 5, national development plan 2007-2013 with the assistance of the European regional development fund. S. Daniels and K.V. Rajani also gratefully acknowledge SFI's Strategic Research Cluster Programme (