Increase of electrochemical catalytic efficiency using phase transition of transition metal oxide film
- 자연과학대학
- Hit2978
- 2017-06-19
Increasing demand for energy and increasing demand for alternative energy, development of the technology is essential. The electrochemical catalytic reaction is the basic operation of the fuel cell, the hydrogen charging device and the storage device. In electrochemical energy evaluation, reaction at cathode in electrolysis is called Oxygen Evolution Reaction (OER). Careful research is needed for an electrochemical reaction since the process of generating anions in the reaction decides efficiency of an overall reaction.
Compared to most of the previous studies which have focused on improving the efficiency of nanostructures that are not well defined by the lattice, the team have synthesized high-quality single crystal materials with well-ordered crystal structures to identify the underlying physicochemical mechanisms of electrochemical catalysis. Furthermore, by introducing atomic defect control method of Pulsed Laser Epitaxy (PLE), other parameters were minimized, and the change of electrochemical catalyst efficiency by lattice and electronic structural phase transition in the same material was confirmed.
(SrRuO3) thin films with perovskite structure were fabricated as high - quality thin films with controlled element defects, and the crystal structure changes due to defects in single thin films were observed. This change in the symmetry of the crystal structure inevitably leads to a change in the electronic structure around the Fermi energy. Such a change in the electronic structure causes a great influence on the electron exchange through adsorption and desorption of oxygen or OH molecules occurring during electrochemical catalysis. In particular, when the symmetry of the lattice structure was changed from orthorhombic to tetragonal, it was confirmed that the energy required for the oxygen generation reaction was reduced by 30% or more. It was confirmed that this is caused by covalent bonding of ruthenium and oxygen in the tetragonal structure or decrease of hybridization of the total population.
The analytical method used in this study will be applicable to other semiconductor materials with layered structure, and it is expected that the time for realizing high performance new material semiconductors will be accelerated.
Through this study, it was confirmed that strong interactions of perovskite oxide, which exhibits a variety of useful physical properties, are essential for energy related research such as oxygen generation reaction. It is also a step closer to understanding the underlying mechanisms of electrochemical catalysis by studying the microscopic lattice structures or electronic structures that are relatively insufficient in energy research.
This study was published in the April issue of Journal Energy & Environmental Science (IF = 25.427, JCR 0.44%).