Barium Cocatalyst Platinum Alumina CNG Exhaust Catalyst
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Solution Overview
Problem
Current catalysts for purifying CNG exhaust gas from lean-burn engines face durability issues due to deactivation, and the causes of this deactivation in platinum/palladium-based catalysts are not accurately identified.
Innovation Solution
A catalyst composition is developed where platinum-impregnated alumina is further impregnated with a barium cocatalyst, along with palladium-impregnated alumina and a ceria component on a ceramic support, to enhance durability, with specific weight ratios and amounts of platinum, palladium, and barium optimized for effective performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a platinum/palladium-based catalyst is used for purifying CNG exhaust gas, then oxidation activity is improved, but catalyst durability deteriorates due to deactivation
Solution Approach 1:
A barium-based cocatalyst is introduced as an intermediary substance that interacts with platinum to prevent deactivation. The barium cocatalyst serves as a mediator between the platinum active sites and the exhaust gas components, preventing harmful interactions that cause deactivation while maintaining oxidation activity.
Solution Approach 2:
The catalyst is designed as a composite material system combining platinum, palladium, barium cocatalyst, and ceramic support. This composite structure allows the barium cocatalyst to work synergistically with the platinum and palladium components, improving both durability and oxidation activity through material interaction.
2Productivity
If noble metal components are loaded on ceramic support, then oxidation activity is enhanced, but catalyst deactivation occurs over time
Solution Approach 1:
The barium cocatalyst ensures continuous useful action by preventing deactivation mechanisms that would otherwise cause catalyst decay over time. This allows the platinum and palladium active sites to maintain their oxidation activity throughout the catalyst's operational lifetime without significant degradation.
Solution Approach 2:
The introduction of the barium cocatalyst changes the chemical and physical parameters of the catalyst system, creating a more stable active site structure that resists deactivation. This parameter change in the catalyst composition directly extends the operational lifetime while maintaining high oxidation activity.
3Reliability
If cocatalyst is added to prevent deactivation, then catalyst durability is improved, but device complexity increases
Solution Approach 1:
The barium cocatalyst is applied locally on the platinum-impregnated alumina particles rather than uniformly throughout the entire catalyst. This localized application provides deactivation prevention where it is most needed at the active sites, while keeping the overall catalyst composition and structure relatively simple.
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 addition of barium as a cocatalyst significantly improves catalyst durability by interacting with platinum, preventing deactivation and maintaining catalytic activity over time, as demonstrated through various tests and durability assessments.
Implementation Method 1
a barium component serving as a cocatalyst is added to a support containing platinum loaded thereon to thus improve catalyst durability
Implementation Method 2
platinum-impregnated first alumina, palladium-impregnated second alumina, and a ceria component are loaded on a ceramic support
Data Source
AI summary
The present invention provides a catalyst composition for inhibiting the inactivation of a catalyst for purification of compressed natural gas combustion system exhaust gas on which a noble metal component comprising platinum and palladium is supported. An oxidation catalyst, for a compressed natural gas vehicle or static combustion system exhaust gas, in which a first alumina impregnated with platinum, a second alumina impregnated with palladium, and a ceria component are supported on a ceramic support, has a barium cocatalyst supported on the first alumina, thereby greatly inhibiting inactivation of a CNG lean burn engine catalyst.