Cu-Based Delafossite Catalyst for Exhaust Gas Purification
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Solution Overview
Problem
Cu-based delafossite-type oxide catalysts exhibit inferior exhaust gas purification performance compared to precious metal catalysts due to lower gas diffusivity, making it challenging to achieve effective purification of NOx and other harmful components in exhaust gases from internal-combustion engines.
Innovation Solution
A novel exhaust gas purification catalyst is developed by combining a Cu-based delafossite-type oxide with an inorganic porous material, where Cu is present in the A site and elements like Mn, Al, Cr, Ga, Fe, Co, Ni, In, La, Nd, Sm, Eu, Y, or Ti are in the B site, enhancing catalytic activity and gas contact probability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If Cu-based delafossite-type oxide is used as exhaust gas purification catalyst, then precious metal can be eliminated, but gas diffusivity is lower and purification performance is inferior
Solution Approach 1:
The patent combines Cu-based delafossite-type oxide with inorganic porous material to form a composite catalyst. The inorganic porous material serves as a carrier that provides high gas diffusivity and large surface area, while the Cu-based delafossite-type oxide maintains its catalytic activity for exhaust gas purification. This composite structure resolves the contradiction by eliminating the need for precious metal while compensating for the low gas diffusivity through the porous material's structure.
Solution Approach 2:
The patent utilizes inorganic porous material with specific pore structure to enhance gas diffusivity. The porous structure provides numerous pathways for gas transport, compensating for the inherently low gas diffusivity of Cu-based delafossite-type oxide. This allows the catalyst to achieve high purification performance without requiring precious metal components.
2Loss of substance
If Cu-based delafossite-type oxide is used alone, then cost is reduced, but contact probability with gas is insufficient
Solution Approach 1:
The inorganic porous material provides a three-dimensional pore network with high surface area-to-volume ratio, dramatically increasing the contact probability between exhaust gas and catalytic sites. The porous structure creates numerous gas flow pathways and increases residence time, enhancing the efficiency of gas-catalyst interaction without increasing material cost.
Solution Approach 2:
The patent transitions from a dense Cu-based delafossite-type oxide structure to a porous composite structure, adding dimensional complexity to the catalyst architecture. This dimensional change creates internal surfaces and pathways that significantly increase gas-catalyst contact probability while maintaining cost-effectiveness.
3Reliability
If Cu content is increased to improve catalytic activity, then purification performance improves, but gas diffusivity further decreases
Solution Approach 1:
The composite structure allows optimization of Cu content within the delafossite-type oxide phase without compromising overall gas diffusivity, because the inorganic porous material provides the primary gas transport pathways. This enables achieving high catalytic activity through increased Cu content while the porous carrier maintains adequate gas diffusivity.
Solution Approach 2:
The patent applies local quality by concentrating Cu-based delafossite-type oxide in specific regions where catalytic activity is needed, while the inorganic porous material forms the continuous matrix responsible for gas transport. This spatial differentiation allows high Cu content in catalytic zones without compromising overall gas diffusivity through the porous matrix.
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 catalyst exhibits improved exhaust gas purification performance, particularly in NOx purification, by maintaining Cu's active dispersion and increasing contact probability with gases, thus overcoming the limitations of using Cu-based delafossite-type oxide alone.
Implementation Method 1
the carbon monoxide (CO) is converted into carbon dioxide by oxidation
Implementation Method 2
A novel exhaust gas purification catalyst is developed by combining a Cu-based delafossite-type oxide with an inorganic porous material, where Cu is present in the A site and elements like Mn, Al, Cr, Ga, Fe, Co, Ni, In, La, Nd, Sm, Eu, Y, or Ti are in the B site, enhancing catalytic activity
Implementation Method 3
the exhaust gas purification catalyst is developed by combining a Cu-based delafossite-type oxide with an inorganic porous material... increasing contact probability with gases
Implementation Method 4
An oxide such as ceria is the OSC material having oxygen storage/release capacity by which trivalent and tetravalent of Ce ions in a crystal lattice are reversibly changed
Data Source
AI summary
Provided is a novel exhaust gas purification catalyst, which uses a Cu-based delafossite oxide, capable of increasing the exhaust gas purification performance compared to the case of using the Cu-based delafossite oxide alone. Proposed is an exhaust gas purification catalyst comprising a delafossite-type oxide represented by a general formula ABO2 and an inorganic porous material, wherein Cu is contained in the A site of the general formula of the delafossite oxide, one or two or more elements selected from the group consisting of Mn, Al, Cr, Ga, Fe, Co, Ni, In, La, Nd, Sm, Eu, Y, V, and Ti are contained in the B site thereof, and Cu is contained in 3 to 30% relative to the total content (mass) of the delafossite-type oxide and the inorganic porous material.