Uncovering Biaxial Strain Effect on Nanoparticle Exsolution for Thin-film Perovskites

Environment-friendly approaches are being advanced to synthesize carbon-neutral fuels. Many of these technologies rely on catalytically highly active nanoparticles that are supported on oxides. A recent advance in such catalyst design is to exsolve catalytic metal nanoparticles at the surface of a supporting oxide. Unlike traditional deposition techniques, the nanoparticle catalysts from exsolution are anchored in the parent oxide. This strong metal-oxide interaction makes the exsolved nanoparticles more resistant against particle agglomeration. In addition, the exsolved particles also open up the possibility of regeneration of catalysts.

In this work, La_0.6Sr_0.4FeO_3-δ (LSF64) thin films are employed as model systems and the biaxial strain is introduced by growing LSF64 thin films epitaxially on substrates with different lattice constants. Coupling surface chemical information from in-situ ambient pressure X-ray spectroscopy with morphological and structural information from electron microscopy, we found that in-plane biaxial strain can be a powerful tool in optimizing the particle dispersion of the exsolution products. The observed strain dependence of exsolution advances our abilities to control them and enhance the performance of catalysts for clean energy technologies.