Ce-Doped La2CuO4 Oxygen Storage Material Thermal Stability
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Solution Overview
Problem
La2CuO4-based oxygen storage materials exhibit reduced oxygen storage capacity when subjected to high-temperature heat durability tests, such as those simulating vehicle exhaust gas catalyst conditions, due to structural breakdown into La2O3 and CuO, which compromises their performance.
Innovation Solution
Replacing some La sites in La2CuO4 with Ce, maintaining a K2NiF4-type crystal structure, and supporting Pt, Pd, or Rh, helps maintain high oxygen storage capacity and thermal durability by enhancing the material's resistance to decomposition during high-temperature tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If La2CuO4 is used as an oxygen storage material, then high oxygen storage capacity is achieved, but thermal durability deteriorates due to structural breakdown at high temperatures
Solution Approach 1:
The patent applies parameter changes by substituting La atoms with Ce atoms in the La2CuO4 crystal structure. This compositional parameter change modifies the material's thermal stability properties, allowing it to maintain structural integrity at high temperatures while preserving oxygen storage capacity. The Ce substitution rate is controlled within specific ranges to optimize both thermal durability and oxygen storage performance.
Solution Approach 2:
The patent creates a composite material system by introducing Ce elements into the La2CuO4 structure, forming a La-Ce-Cu-O composite oxide. This composite approach combines the high oxygen storage capacity of La2CuO4 with the thermal stability benefits of Ce-containing phases, resolving the contradiction between oxygen storage capacity and thermal durability through synergistic material design.
2Quantity of substance
If La2CuO4 is used as an oxygen storage material, then high oxygen storage capacity is achieved, but structural stability deteriorates due to decomposition into La2O3 and CuO
Solution Approach 1:
The patent changes the compositional parameter by substituting La with Ce at specific sites in the crystal structure. This parameter change stabilizes the K2NiF4-type structure against decomposition into La2O3 and CuO by modifying the chemical bonding and structural framework, thereby maintaining structural stability while preserving oxygen storage capacity.
Solution Approach 2:
Ce acts as an intermediary element that mediates between the La2CuO4 structure and the harsh high-temperature environment. The Ce substitution creates a more stable intermediate structure that resists direct decomposition into La2O3 and CuO, effectively protecting the oxygen storage functionality under thermal stress.
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 modified La2CuO4 composition with Ce substitution and metal support maintains high oxygen storage capacity and crystallinity even at high temperatures, outperforming unmodified La2CuO4 in heat durability tests, as evidenced by sustained oxygen storage capacity and X-ray diffraction patterns.
Implementation Method 1
maintaining a K2NiF4-type crystal structure... enhances the material's resistance to decomposition during high-temperature tests
Implementation Method 2
Metal oxides used in such composite oxides include oxygen storage materials, which allow absorption and release of oxygen in response to the oxygen partial pressure in the atmosphere
Implementation Method 3
Pt, Pd or Rh is supported thereon... exhaust gas purification catalyst
Data Source
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AI summary
The invention provides an oxygen storage material having high oxygen storage capacity and high thermal durability. The oxygen storage material of the invention has some of the La sites of La2CuO4 with a K2NiF4-type crystal structure replaced by Ce. The oxygen storage material may have the composition La(2.00-x)CexCuO4 (0.20 ≥ x > 0.00). The oxygen storage material may also have a precious metal supported. The precious metal may be Pt, Pd or Rh. The exhaust gas purification catalyst is an exhaust gas purification catalyst comprising an oxygen storage material according to the invention.