(545b) Enhancing Stability in Gas-Phase Reactions By Mitigating Metal Sintering Via Exsolution

Exsolution, a process whereby metal nanoparticles are liberated from ceramic hosts under specific reduction conditions, is a noteworthy phenomenon. These exsolved metal particles establish distinctive interfaces with perovskite hosts, either integrating into the surfaces or forming new chemical bonds. Not only do these nanoparticles offer abundant and uniformly dispersed catalytic active sites on oxide surfaces, but they also demonstrate robust thermal and redox stability.

Our ongoing investigation revolves around Pt exsolution catalysts supported by LaFeO₃ perovskite, showcasing exceptional endurance in demanding conditions, particularly in high-temperature water gas shift (HT-WGS) reactions. Structural analyses have unveiled significant preservation of particle dispersion upon exsolution, indicating an advantage in preventing metal sintering. To delve into the mechanisms enabling exsolution particles to maintain stability during reactions, we conducted diverse analyses such as in situ EXAFS, in situ DRIFT, density functional theory, and machine learning potential based molecular dynamics, focusing on factors like variations in intermediates, reaction pathways, and reactant sensitivity. Our ultimate aim is to pinpoint the reasons behind reduced coking tendencies.

These findings emphasize the remarkable stability of exsolution particles in HT-WGS environments and potential benefits in water or hydrocarbon-related reactions. Notably, their prospective integration into various catalytic applications holds substantial promise for addressing challenges such as metal particle agglomeration and coking.