Dislocations govern noble metal exsolution in perovskite oxide

Abstract Self-assembled metal nanoparticles exsolved from host oxides have gained prominence in catalysis and electrochemistry owing to their exceptional activity and stability1–3. Understanding the relation between dopant transport and exsolution is important, as the transport mechanism of dopants toward the surface of the host oxide directly influences exsolution sites, density, and dispersion, ultimately determining catalytic functionality4–6. However, the pathways for dopant transport and their interaction with internal defects during exsolution remain unclear because of the complexity of defects hidden in bulk. Here, we reveal the exsolution pathway mediated by dislocation evolution within a host oxide perovskite. By employing in situ Bragg coherent X-ray diffraction imaging and transmission electron microscopy, we show that dislocations nucleate in the bulk interior and propagate to the surface during the reduction of Ru-doped in BaCe0.85Y0.1Ru0.05O3-δ. Moreover, we verify that the Ru dopant is specifically correlated with the formation of mixed dislocations, which then provide transport pathways for the exsolution of Ru nanoparticles. These findings advance our understanding of dislocation dynamics and support the development of exsolved metal nanoparticles for next-generation catalysts7,8.