Thermal stability and coalescence dynamics of exsolved metal nanoparticles at charged perovskite surfaces

Metal exsolution reactions can activate oxides for electrocatalysis by nucleating finely dispersed nanoparticles on the oxide surface, which is relevant for green hydrogen-based energy technologies.

However, both nanoparticle exsolution and nanoparticle coalescence—a process that decreases nanoparticle density and degrades catalytically active triple-phase boundaries—are driven by the reaction conditions. Therefore, preventing nanoparticle coalescence is essential to maintain the performance of these catalysts over their operational lifespan.

In our latest study, we demonstrate that coalescence behavior is influenced by the surface defect chemistry of the exsolution-active oxide and the oxophilicity of the exsolved metal. We reveal that oxygen vacancy defects, i.e., empty sites in the oxide crystal’s oxygen sublattice, play a critical role in this process. These defects modify the local bonding, decreasing the thermal stability of exsolved nanoparticles and making them more prone to coalescence.

We highlight current limitations in existing exsolution synthesis routes and propose easily implementable strategies for achieving better control over metal exsolution reactions.

Link to the article: https://www.nature.com/articles/s41467-024-54008-4