Abstract
The formation and study of oxygen vacancies are critical for the development of enhanced functional oxides; in the oxygen evolution reaction (OER), oxygen vacancies are proposed to influence the activity and degradation of electrocatalysts. We use thin films of state-of-the-art OER catalyst SrIrO3 deposited on crystal substrates with varied lattice parameters to demonstrate the effect of epitaxial strain on oxygen vacancy formation. Through in situ x-ray diffraction under elevated temperatures and reducing conditions of 3% H2/balance N2, we show that tensile epitaxial strain makes oxygen vacancy formation more favorable, whereas compressive epitaxial strain has no significant effect compared with an unstrained film. We further use in situ and ex situ x-ray absorption spectroscopy to reveal the effect of strain on the favorability of full reduction of Ir species within SrIrO3 films from Ir4+ to Ir0 and on the energy levels of unoccupied electronic states in the out-of-plane direction, respectively. This study adds experimental evidence for the link between strain and oxygen vacancy formation in 5d thin film perovskites, for which the discussion has been dominated by theory-based approaches.
| Original language | English (US) |
|---|---|
| Article number | 055801 |
| Journal | Physical Review Materials |
| Volume | 8 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2024 |
Funding
Portions of this work were performed at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by Northwestern University, The Dow Chemical Company, and DuPont de Nemours, Inc. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This work made use of the SPID facility of Northwestern University's NUANCE Center, which has received support from the SHyNE Resource (NSF Grant No. ECCS-2025633), the IIN, and Northwestern's MRSEC program (NSF Grant No. DMR-2308691). This work made use of the Jerome B. Cohen X-Ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (Grant No. DMR-2308691) at the Materials Research Center of Northwestern University and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF Grant No. ECCS-1542205.) Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. This work made use of the Pulsed Laser Deposition Shared Facility at the Materials Research Center at Northwestern University supported by the National Science Foundation MRSEC program (Grant No. DMR-1720139) and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF Grant No. ECCS-2025633). This work was partially funded by NSF CAREER Award No. 2144365-CBET.
ASJC Scopus subject areas
- General Materials Science
- Physics and Astronomy (miscellaneous)
