1 research outputs found
Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials
No full textPerovskite oxides can exhibit a wide range of interesting
characteristics
such as being catalytically active and electronically/ionically conducting,
and thus, they have been used in a number of solid-state devices such
as solid oxide fuel cells (SOFCs) and sensors. As the surface compositions
of perovskites can greatly influence the catalytic properties, knowing
and controlling their surface compositions is crucial to enhance device
performance. In this study, we demonstrate that the surface strontium
(Sr) and cobalt (Co) concentrations of perovskite-based thin films
can be controlled reversibly at elevated temperatures by applying
small electrical potential biases. The surface compositional changes
of La<sub>0.8</sub>Sr<sub>0.2</sub>CoO<sub>3−δ</sub> (LSC<sub>113</sub>), (La<sub>0.5</sub>Sr<sub>0.5</sub>)<sub>2</sub>CoO<sub>4±δ</sub> (LSC<sub>214</sub>), and LSC<sub>214</sub>-decorated
LSC<sub>113</sub> films (LSC<sub>113/214</sub>) were investigated
in situ by utilizing synchrotron-based X-ray photoelectron spectroscopy
(XPS), where the largest changes of surface Sr were found for the
LSC<sub>113/214</sub> surface. These findings offer the potential
of reversibly controlling the surface functionality of perovskites
