Understanding electrochemical switchability of perovskite-type exsolution catalysts.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32968079.
- Also identified by DOI 10.1038/s41467-020-18563-w and PMC identifier 7511332.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Exsolution of metal nanoparticles from perovskite-type oxides is a very promising approach to obtain catalysts with superior properties. One particularly interesting property of exsolution catalysts is the possibility of electrochemical switching between different activity states. In this work, synchrotron-based in-situ X-ray diffraction experiments on electrochemically polarized La<sub>0.6</sub>Sr<sub>0.4</sub>FeO<sub>3-δ</sub> thin film electrodes are performed, in order to simultaneously obtain insights into the phase composition and the catalytic activity of the electrode surface. This shows that reversible electrochemical switching between a high and low activity state is accompanied by a phase change of exsolved particles between metallic α--Fe and Fe-oxides. Reintegration of iron into the perovskite lattice is thus not required for obtaining a switchable catalyst, making this process especially interesting for intermediate temperature applications. These measurements also reveal how metallic particles on La<sub>0.6</sub>Sr<sub>0.4</sub>FeO<sub>3-δ</sub> electrodes affect the H<sub>2</sub> oxidation and H<sub>2</sub>O splitting mechanism and why the particle size plays a minor role.