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Updated: Jul 17, 2025
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Synthesis and Reaction Chemistry of Nanosize Monosodium Titanate
Published on: February 23, 2016
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Oxidation Kinetics of Nanocrystalline Hexagonal RMn1-TiO3 (R = Ho, Dy).
Frida Hemstad Danmo1, Inger-Emma Nylund1, Aamund Westermoen1
1Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
ACS Applied Materials & Interfaces
|August 28, 2023
Summary
Hexagonal manganites show promise for energy-efficient air separation. Ti4+-doping and larger rare earth cations significantly improve their oxygen exchange kinetics at lower temperatures.
Area of Science:
- Materials Science
- Solid-state Chemistry
- Chemical Engineering
Background:
- Hexagonal manganites (RMnO3) exhibit reversible oxygen storage, crucial for air separation.
- Current methods are energy-intensive; these materials offer lower-temperature (250-400 °C) operation.
- Slow oxygen exchange kinetics at low temperatures limit their practical application.
Purpose of the Study:
- To enhance the oxidation kinetics of hexagonal manganites for improved air separation efficiency.
- To investigate the effects of rare earth cation size and Ti4+ doping on oxygen exchange rates.
- To understand the underlying mechanisms responsible for kinetic improvements.
Main Methods:
- Thermogravimetric analysis (TGA) to measure oxygen absorption rates.
- X-ray absorption near-edge structure (XANES) for electronic state analysis.
- High-temperature X-ray diffraction (HT-XRD) with in situ atmosphere switching to monitor lattice changes and determine kinetics.
Main Results:
- Increasing rare earth cation size and Ti4+ doping enhance oxidation kinetics.
- Ti4+ doping significantly accelerates the oxygen absorption rate.
- Lattice expansion, particularly in the ab-plane, correlates with improved oxygen ion migration due to reduced electrostatic repulsion.
Conclusions:
- Ti4+-doping and larger rare earth cations are effective strategies to boost the performance of hexagonal manganites for oxygen storage.
- The observed kinetic improvements are attributed to structural modifications facilitating oxygen ion mobility.
- These findings pave the way for more efficient and energy-saving air separation technologies.
Keywords:
hexagonal manganitesoxidation kineticsoxygen absorptionoxygen exchangeoxygen storage materialsMore Related Videos
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