Nanoparticle Exsolution from Nanoporous Perovskites for Highly Active and Stable Catalysts

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Nanoporosity is crucial for heterogeneous catalyst performance.
• Exsolution is a modern catalyst design method, often studied in sintered matrices.
• This study focuses on nanoporous perovskite oxides for exsolution.

Purpose of the Study:

• To quantitatively describe nickel nanoparticle exsolution from nanoporous perovskite oxides.
• To evaluate the application of these catalysts in biogas dry reforming.
• To compare the performance of nanoporous versus sintered exsolved catalysts.

Main Methods:

• Exsolution process studied between 500–900 °C in nanoporous and sintered La_0.52 Sr_0.28 Ti_0.94 Ni_0.06 O_3±δ.
• Temperature-programmed reduction (TPR) and X-ray absorption spectroscopy (XAS) for analyzing oxygen release and Ni reduction.
• In situ transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) for nanoparticle formation mechanism study.

Main Results:

• Nanoporous materials exhibit twice the Ni reduction compared to sintered ones due to faster, larger oxygen release.
• Nanoparticle formation in nanoporous materials follows classical nucleation theory.
• Nanoporous exsolved catalysts achieve 18x higher activity and 90% CO₂ conversion at 800 °C in biogas reforming.

Conclusions:

• Nanoporous perovskite oxides enable highly effective exsolution of Ni nanoparticles.
• These catalysts demonstrate superior activity, stability, and regenerability for biogas dry reforming compared to commercial alternatives.
• The findings highlight the potential of nanoporous materials for advanced catalytic applications.