Abstract
Single-crystalline transition metal oxide thin film has been employed to perceive the fundamental functions of electronic structure and charge transfer processes in water splitting processes. However, the surface area enlargement and strain tunabilitv in a single-crystalline transition metal oxide are restricted in conventional epitaxy. In this study, we report the oxygen evolution reaction (OER) enhancement by a stack of multilayer SrRuO3 featured single- crystallinity, flexibility, and stackability. The controllable stack of multiple cylindrical SrRuO3 for surface enlargement in a magnitude of order and the emergent electronic structure transition, from t_(2g)(3↑, 1↓) to t_(2g)(3↑)eg(1↓), of Ru efficiently enhances the OER performance, the overpotential can be reduced by ～74 % and ～78 % in KOH and HClO4 respectively at 5 mA/cm~2. Our study provides an approach for fine manipulation of single-crystalline freestanding oxide morphologically, and an efficient strategy aiming at the extreme enhancement of the electrochemically active surface area and the electronic structure engineering by strain.
NSTL