Apatite-Type Composite Oxide for Low-Temperature Oxygen Storage
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Solution Overview
Problem
Existing oxygen storage materials, such as ceria-zirconia composite oxides, face challenges including high costs due to the use of rare metals like zirconium, high activation energy for oxygen release, and instability leading to low oxygen storage amounts.
Innovation Solution
A composite oxide with an apatite-type crystalline structure containing cerium and/or europium and silicon and/or phosphorus is developed, which has a lower activation energy for oxygen release and exhibits excellent oxygen storage and release properties at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ceria-zirconia composite oxide with pyrochlore phase is used as oxygen storage material, then oxygen storage capacity is improved, but manufacturing cost increases due to use of rare metal zirconium
Solution Approach 1:
The patent replaces expensive rare metal zirconium with cheaper common metals such as aluminum, calcium, or magnesium in the oxygen storage material composition, while maintaining adequate oxygen storage capacity through optimized formulation of the composite oxide system
Solution Approach 2:
The patent develops composite oxide materials combining ceria with oxides of common metals (alumina, calcium oxide, magnesium oxide, etc.) to create a composite structure that achieves oxygen storage functionality without relying on rare metals like zirconium
2Quantity of substance
If ceria-zirconia composite oxide with pyrochlore phase is used as oxygen storage material, then oxygen storage capacity is improved, but oxygen release temperature increases due to high activation energy
Solution Approach 1:
The patent modifies the chemical composition parameters of the oxygen storage material by substituting zirconium with other metal oxides and adjusting the ratios of components to reduce activation energy for oxygen release, enabling oxygen release at lower temperatures while preserving storage capacity
Solution Approach 2:
The patent creates a composite oxide structure where different metal oxide components perform specialized functions: ceria provides oxygen storage capacity while other metal oxides (alumina, calcium oxide, etc.) facilitate oxygen release at lower temperatures through their specific crystal structures and surface properties
3Ease of manufacture
If melilite-type oxide with abundant elements is used as oxygen storage material, then manufacturing cost decreases, but oxygen storage amount reduces due to composition instability
Solution Approach 1:
The patent creates a composite oxide system combining ceria with stable metal oxides (alumina, calcium oxide, magnesium oxide) in specific proportions to achieve both cost-effectiveness using abundant elements and sufficient oxygen storage capacity through the synergistic interaction of components
Solution Approach 2:
The patent optimizes the compositional parameters including the ratios of metal oxides and the overall stoichiometry to enhance the stability of the composite oxide structure while maintaining high oxygen storage capacity, preventing the instability issues observed in simpler melilite-type oxides
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apatite-type composite oxide achieves efficient oxygen release at low temperatures with a significant oxygen storage capacity, addressing the cost and stability issues of previous materials.
Implementation Method 1
a composite oxide having an apatite-type crystalline structure containing Ce and/or europium (Eu) and silicon (Si) and/or phosphorus (P) has a smaller activation energy than Ce2Zr2O7 having a pyrochlore-type crystalline structure containing Ce and Zr useful as a conventional oxygen storage material, and has an excellent oxygen storage property and oxygen release property at low temperature
Data Source
AI summary
Provided is an inexpensive oxygen storage material having an excellent oxygen release performance at low temperature. The present disclosure relates to an oxygen storage material containing a composite oxide. The composite oxide contains cerium and/or europium and silicon and/or phosphorus. The composite oxide has an apatite-type crystalline structure.