Exhaust Gas Purifying Catalyst Composite Oxide
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Solution Overview
Problem
Conventional ternary catalysts fail to effectively remove toxic components from exhaust gas at low temperatures and exhibit decreased performance over a wide temperature range due to heat deterioration, leading to inconsistent exhaust gas purification.
Innovation Solution
A catalyst comprising a composite oxide represented by the formula (Aa-w-xMwM′x)(Si6-yNy)O27-z, where A is La or Pr, M is Ba, Ca, or Sr, M′ is Nd, Y, Al, Pr, Ce, Sr, or Ca, and N is Fe, Cu, or Al, with a noble metal component forming a solid solution or supported on the composite oxide, providing high low-temperature activity and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional ternary catalysts are used, then the catalyst structure is simple, but the catalyst fails to remove toxic components effectively at low temperatures
Solution Approach 1:
The patent employs a composite oxide with apatite-type structure containing multiple elements (La, Pr, Ba, Ca, Sr, Si, Al, Fe, Cu) combined with noble metals (Pt, Pd, Rh) to create a catalyst that achieves high low-temperature activity. The complex composite oxide structure provides both structural stability and high catalytic activity at low temperatures, resolving the contradiction between structural simplicity and low-temperature performance.
2Ease of manufacture
If conventional ternary catalysts are used, then the catalyst is easy to manufacture, but the catalyst exhibits lowered performance at high temperatures due to deterioration
Solution Approach 1:
The composite oxide with apatite-type structure containing La, Pr, Ba, Ca, Sr, Si, Al, Fe, and Cu provides excellent heat resistance and structural stability at high temperatures. This complex composite structure prevents catalyst deterioration and maintains consistent performance across a wide temperature range, solving the contradiction between ease of manufacture and high-temperature reliability.
3Device complexity
If conventional ternary catalysts are used, then the catalyst structure is simple, but the catalyst fails to attain consistent purification performance across temperature ranges
Solution Approach 1:
The patent uses a complex composite oxide structure with multiple elements in specific ratios to achieve consistent exhaust gas purification performance across both low and high temperature ranges. The multi-element composition provides both low-temperature activity and high-temperature stability, eliminating the performance inconsistency problem.
4Use of energy by stationary object
If the catalyst operates at low temperature immediately after engine start, then energy consumption is reduced, but the catalyst cannot effectively remove toxic components
Solution Approach 1:
The catalyst composition is specifically designed with a composite oxide structure that changes its operational parameters to enable effective catalysis at low temperatures. The multi-element composite structure modifies the catalyst's active sites and reaction mechanisms, allowing it to remove toxic components efficiently even when the catalyst temperature is low, thus resolving the contradiction between energy consumption and purification efficiency.
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 achieves consistent exhaust gas purification performance across a low to high temperature range, effectively removing toxic components such as C3H6 and NOx, demonstrating high catalytic activity and durability.
Implementation Method 1
a noble metal ingredient which forms a solid solution with the composite oxide or is supported on the composite oxide
Data Source
AI summary
An exhaust gas purifying catalyst includes: a composite oxide represented by: (Aa-w-xMwM′x) (Si6-yNy)O27-z. A is a cation of at least one of La and Pr; M is a cation of at least one of Ba, Ca, and Sr; M′ is a cation of at least one of Nd, Y, Al, Pr, Ce, Sr, Li, and Ca; N is a cation of at least one of Fe, Cu, and Al. The following are satisfied: 6≦a≦10, 0<w<5, 0≦x<5, 0<w+x≦5, 0≦y≦3, 0≦z≦3, A≠M′, and x≠0 when A is a cation of La. A noble metal ingredient which forms a solid solution with the composite oxide or is supported on the composite oxide, and an exhaust gas purifying catalyst product formed of a carrier made of a ceramic or metallic material, and a layer of the exhaust gas purifying catalyst supported on the carrier.