Nanoparticles to Aggregates: Solid‑State Mechanisms Driving Thermal Sintering in Catalytic Material

Jonelle Brown

Co-Presenters: Individual Presentation

College: Hennings College of Science Mathematics and Technology

Major: BA.CHEM/PREPROF

Faculty Research Mentor: Mongelli, Matthew  Stokes-Huby, Heather

Abstract:

Thermal sintering remains a primary cause of deactivation in nanoparticle-based heterogeneous catalysts. Elevated temperatures drive the transformation of discrete nanoparticles into larger, less effective aggregates. Catalytic activity is dependent on surface-to-volume ratios, and the structural evolution caused by sintering reduces the number of accessible active sites. These aggregates reduce catalyst performance and limit long-term stability in industrial applications. This work examines the solid-state mechanisms that govern thermal sintering, including particle migration, coalescence, Ostwald ripening and diffusion-driven restructuring. The thermodynamic driving forces are discussed alongside critical kinetic pathways underlying these processes. Emphasis is placed on the roles of support composition and interfacial bonding in particle mobility and growth. Techniques such as transmission electron microscopy and X-ray diffraction provide insight into structural changes during high-temperature exposure. Strategies to mitigate sintering, including strong metal–support interactions, encapsulation, and alloy design, are also discussed. Understanding these mechanisms at the atomic and nanoscale levels are essential for the rational design of thermally stable catalytic materials.