Oxidation Catalyst Phosphorus Trap Zone Segmentation
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Solution Overview
Problem
Existing oxidation catalysts for diesel engine exhaust gases are susceptible to phosphorus contamination, which impairs their oxidation capability over their service life.
Innovation Solution
A catalyst with a carrier substrate having two material zones, A and B, where zone B has a higher loading of platinum group metals and a specific pore structure, effectively acting as a phosphorus trap to protect the catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxidation catalysts are used to treat diesel exhaust gases, then carbon monoxide and hydrocarbons are oxidized, but phosphorus contamination from oil additives deposits on the catalyst and impairs its oxidation capability over service life
Solution Approach 1:
The catalyst is divided into two distinct material zones along the exhaust gas flow direction: a first material zone with lower platinum group metal loading (40-150 g/l) and a second material zone with higher platinum group metal loading (75-200 g/l). This segmentation allows each zone to serve different functions - the first zone handles initial oxidation while the second zone provides enhanced oxidation capacity and phosphorus trapping, thereby maintaining reliability despite phosphorus contamination.
Solution Approach 2:
The catalyst exhibits spatially varying properties: the second material zone has both higher platinum group metal content (0.53-2.5 g/l) and specific pore structure (20-30% pore proportion with 0.5-50 μm diameter) compared to the first zone. This local quality enhancement in the second zone creates a phosphorus trap that protects the overall catalyst from deactivation, while maintaining high oxidation capability throughout.
2Productivity
If higher loading of platinum group metals is used in the catalyst, then oxidation efficiency is improved, but the catalyst becomes more susceptible to phosphorus deposition and deactivation
Solution Approach 1:
The catalyst is divided into two distinct material zones along the exhaust gas flow direction: a first material zone with lower platinum group metal loading (40-150 g/l) and a second material zone with higher platinum group metal loading (75-200 g/l). This segmentation allows each zone to serve different functions - the first zone handles initial oxidation while the second zone provides enhanced oxidation capacity and phosphorus trapping, thereby maintaining reliability despite phosphorus contamination.
Solution Approach 2:
The catalyst exhibits spatially varying properties: the second material zone has both higher platinum group metal content (0.53-2.5 g/l) and specific pore structure (20-30% pore proportion with 0.5-50 μm diameter) compared to the first zone. This local quality enhancement in the second zone creates a phosphorus trap that protects the overall catalyst from deactivation, while maintaining high oxidation capability throughout.
3Ease of manufacture
If the catalyst is designed with uniform platinum group metal loading, then manufacturing is simplified, but phosphorus contamination uniformly deactivates the entire catalyst surface over time
Solution Approach 1:
The catalyst is divided into two distinct material zones along the exhaust gas flow direction: a first material zone with lower platinum group metal loading (40-150 g/l) and a second material zone with higher platinum group metal loading (75-200 g/l). This segmentation allows each zone to serve different functions - the first zone handles initial oxidation while the second zone provides enhanced oxidation capacity and phosphorus trapping, thereby maintaining reliability despite phosphorus contamination.
Solution Approach 2:
The catalyst exhibits spatially varying properties: the second material zone has both higher platinum group metal content (0.53-2.5 g/l) and specific pore structure (20-30% pore proportion with 0.5-50 μm diameter) compared to the first zone. This local quality enhancement in the second zone creates a phosphorus trap that protects the overall catalyst from deactivation, while maintaining high oxidation capability throughout.
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 is highly resistant to phosphorus contamination, maintaining its oxidation efficiency throughout its service life, as demonstrated by comparative tests showing prolonged resistance to phosphorus exposure.
Implementation Method 1
carbon monoxide and hydrocarbons are rendered harmless by oxidation in a suitable oxidation catalyst
Implementation Method 2
carbon monoxide and hydrocarbons are rendered harmless by oxidation in a suitable oxidation catalyst
Implementation Method 3
a phosphorus trap, wherein a second material zone B... effectively acting as a phosphorus trap to protect the catalyst
Data Source
AI summary
The present invention relates to a catalyst, which comprises * a carrier substrate with a first end a and a second end b, and length L, * a material zone A containing a platinum group metal on a support material with a load of 40 to 150 g/l, relative to the volume of the carrier substrate and * material zone B containing a platinum group metal on a support material with a load of 75 to 200 g/l, relative to the volume of the carrier substrate, wherein material zone B has a greater content of platinum group metal, relative to the volume of the carrier substrate and calculated in g/l, than material zone A, and wherein material zone B has a proportion of pores with a diameter of 0.5 to 50 μm of 20 to 30%.