In Situ TEM Study of Rh Particle Sintering for Three-Way Catalysts in High Temperatures

Tuesday publication update! In this publication in #Catalysts the authors are investigating the longevity and efficiency of automobile three-way catalysts, trying to understand the factors behind their deterioration. One major challenge is the sintering of platinum group metals (PGMs), particularly rhodium (Rh) particles, under high-temperature conditions. Visualizing this with #insitugasphaseTEM and our #AtmosphereAX system gives the befenit to compare their bulk to nanoscale results!

Two distinct environmental conditions were explored: a vacuum atmosphere heated up to 1050°C and an N2 atmosphere with/without 1% O2 at 1 atm, heated up to 1000°C.

️Under Vacuum: Rh particles appeared immersed in ZrO2, suggesting a strong interaction with the support material.

☁️In N2 Atmosphere: The Rh particles sintered into spherical shapes, not immersed in ZrO2, mirroring the morphology observed in actual engine-aged catalysts. Intriguingly, the sintering of support material (ZrO2 or Y-ZrO2) was observed first, followed by Rh particle sintering.
Additionally, the size of Rh particles was slightly smaller on Y-ZrO2 compared to ZrO2, indicating the impact of support material composition on sintering behavior.

Density functional theory (DFT) was additionally used to calculate the junction energies of Rh(111) structures on ZrO2 and Y-ZrO2. The calculated energies aligned well with the in situ TEM findings in the N2 atmosphere, providing a theoretical foundation for the experimental results.

Studies like these help understand sintering and therefore deactivation in catalysts. In turn this can lead to mitigating sintering effects, which can significantly extend the lifespan and performance of automobile catalysts.

Want to read the entire publication?
Find it here:
https://www.mdpi.com/2073-4344/11/1/19

#findyourbreakthrough #Protochips #carcatalysts #heterogeneouscatalysts #insitugasphaseTEM #TEM #STEM #insituTEM