B-site modulation tailors the size distribution of ex-solved nanoparticles for optimized active sites in perovskites

Supported nanoparticles fabricated by an ex-solution process from perovskite scaffolds serve promising capabilities for various thermal and electrochemical reactions. Although the size distribution of the nanoparticles plays a crucial role in catalysis, it remains difficult to control in ex-solution due to the lack of understanding of their underlying energetic factors. Here, we investigate the impact of B-site doping in two different types of perovskite hosts (A²⁺B⁴⁺O₃ and A³⁺B³⁺O₃) on the size distribution of ex-solved nanoparticles. By incorporating non-reducible ions at the B-site, we observe the variations in nanoparticles' sizes and densities using model cleaved surfaces of ceramic pellets. Density functional theory calculations help correlate the observed experimental results with the computed energetic descriptors, providing deeper insights into the particle ex-solution and enabling the description of particle density via a first-order nucleation model. Furthermore, we utilize the tailored ex-solution materials as catalysts for N₂O decomposition, and it exhibits a volcano-plot relationship between the catalytic activity and size distribution of ex-solution particles. It suggests that our findings can provide an alternative way to optimizing catalytic active sites for various environmental and energy applications.