MIEC Composite Oxides for Redox Fuel Conversion
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Solution Overview
Problem
Current strategies for designing oxygen carriers and redox catalysts in cyclic redox processes lack effective methods for achieving optimal stability, strength, reactivity, and selectivity, which are crucial for efficient carbon dioxide capture and fuel conversion.
Innovation Solution
The development of mixed ionic-electronic conductive (MIEC) oxides, either in composite or core-shell forms, that act as both oxygen carriers and catalysts, utilizing transition metal oxides and perovskite structures to enhance redox activity and product selectivity, with specific formulations like Fe2O3-La0.7Sr0.3FeO3 and BaCe0.7Fe0.3O3, and preparation methods such as solid state reaction and sol-gel synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional inert support mixing is used to achieve stability and strength, then mechanical strength and thermal stability are improved, but reactivity and selectivity deteriorate
Solution Approach 1:
The patent employs composite materials by combining transition metal oxides (Fe2O3, MnO2, Co3O4) with mixed ionic-electronic conductive perovskite supports (La0.7Sr0.3FeO3, BaCe0.7Fe0.3O3). This composite structure allows the metal oxides to provide high reactivity while the perovskite support provides thermal stability and mechanical strength, resolving the contradiction between stability and reactivity.
Solution Approach 2:
The patent applies local quality by creating core-shell structures where the transition metal oxide forms the core (providing reactivity) and the perovskite material forms the shell (providing stability). This spatial differentiation allows each component to fulfill its specific function optimally without compromising the other.
2Productivity
If high reactivity oxygen carriers are used to improve fuel conversion, then productivity is improved, but structural stability and mechanical strength deteriorate
Solution Approach 1:
The patent uses composite materials where reactive transition metal oxides are combined with stable perovskite supports. The perovskite structure provides a stable framework that maintains structural integrity during cyclic redox operations, while the metal oxide cores provide high reactivity for fuel conversion.
Solution Approach 2:
The core-shell structure concentrates reactivity in the metal oxide core while the perovskite shell provides structural stability. This local differentiation ensures that high reactivity does not compromise structural integrity.
3Productivity
If conventional redox catalysts are used to achieve fuel conversion, then productivity is improved, but selectivity and resistance to deactivation deteriorate
Solution Approach 1:
The patent changes the chemical and physical parameters of the catalyst by using specific transition metal oxides with controlled oxidation states and combining them with perovskite supports having specific ionic and electronic conductivities. This parameter optimization enhances both fuel conversion productivity and product selectivity while improving resistance to deactivation.
Solution Approach 2:
The composite structure allows tuning of catalytic properties by selecting specific metal oxide/perovskite combinations. The perovskite support modifies the electronic structure of the metal oxide, enhancing selectivity for desired products while maintaining high productivity.
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
These MIEC oxides demonstrate improved structural and chemical stability, tunable thermodynamic properties, and superior redox activity, enabling efficient conversion of fuels like natural gas and biomass into value-added products such as hydrogen and syngas, while maintaining high selectivity and resistance to deactivation.
Implementation Method 1
These processes utilize the transfer of oxygen from air and/or water to the fuel through cyclic redox operations of solid oxygen carriers
Implementation Method 2
a mixed ionic-electronic conductive (MIEC) support... a mixed ionic-electronic conductive (MIEC) shell
Data Source
AI summary
Compositions and methods for preparing and using ceramic mixed ionic-electronic conductor (MIEC) enhanced transition metals and metal oxides in composite or core-shell forms are disclosed. The presently disclosed compositions are stable at high temperatures and can carry as much as about 20 weight % oxygen.