Electronic Structure Dependent Electrocatalytic Activity in Perovskite Ruthenate Epitaxial Thin Films

Defect engineering in transition metal oxides provides facile ways to control the crystal and electronic structures which leads to a modification of physical and chemical properties of interest. In particular, perovskite Ruthenates are interesting model systems where both A- and B-site ionic concentration can be modified through the epitaxial film growth control, to further tailor the electronic, magnetic, and structural properties via strong coupling among different degrees of freedom [1]. In this presentation, we show that a strong correlation exists even between the physical and chemical properties of the epitaxial ARuO₃ (A = Sr and Ca) thin films. Particularly, the electrocatalytic activity was found to be strongly dependent on the changes in the electronic structure of the epitaxial ARuO₃ thin films induced by elemental vacancy via pulsed laser epitaxy. The strong hybridization between the Ru 4d and O 2p states critically influence the oxygen evolution reaction, providing an activity descriptor for the electrochemical activity [2]. We believe that our results help to understand the fundamental correlation between the electronic structure and the catalytic reaction.
[1] S. A Lee et al., Sci. Rep. 7, 11856 (2017).
[2] S. A Lee et al., Energ. Environ. Sci. 10, 924–930 (2017).