CNG Catalyst Barium Cocatalyst Palladium Electron State
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Solution Overview
Problem
Catalysts for purifying exhaust gas from compressed natural gas (CNG) lean burn engines containing platinum (Pt) and palladium (Pd) face durability issues due to deactivation, with the causes of this deactivation not accurately identified.
Innovation Solution
A ceramic substrate impregnated with Pd-impregnated first alumina, Pt-impregnated second alumina, and ceria powder, with barium added as a cocatalyst to Pd-impregnated first alumina, altering the electron state of Pd and inhibiting deactivation, maintaining catalytic activity over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional catalyst containing Pt and Pd is used for purifying CNG exhaust gas, then methane purification efficiency is satisfactory, but catalyst durability decreases due to deactivation
Solution Approach 1:
The invention changes the chemical composition parameter by introducing barium as a cocatalyst component. This modifies the electronic state of Pd and creates new active sites, fundamentally altering the catalyst's chemical properties to prevent deactivation while maintaining purification efficiency
Solution Approach 2:
The invention creates a composite catalyst structure combining multiple components: Pt-impregnated alumina, Pd-impregnated alumina, ceria powder, and barium cocatalyst. This composite approach synergistically combines the oxidation capabilities of Pt and Pd with the structural stability of alumina, the oxygen storage capacity of ceria, and the electron-state-modifying effect of barium to achieve both high efficiency and durability
2Productivity
If Pt and Pd are used as precious metal components for methane purification, then purification efficiency is improved, but catalyst deactivation occurs over time
Solution Approach 1:
The barium cocatalyst acts as an intermediary that modifies the electronic environment of Pd. By changing the electron state of Pd through barium interaction, the catalyst maintains its high purification efficiency while the barium component prevents the deactivation that would otherwise occur with Pt and Pd alone
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 inhibits deactivation, maintaining catalytic activity and methane conversion efficiency in CNG lean burn engine catalysts, outperforming comparative cocatalysts like nickel, lanthanum, samarium, and yttrium.
Implementation Method 1
a barium cocatalyst is added to thus change the electron state of Pd, serving as the precious metal, thereby inhibiting the deactivation of the catalyst
Implementation Method 2
a ceramic substrate is impregnated with a supporting material, such as alumina, ceria or zirconia, and a precious metal, serving as a catalytically active material, in order to efficiently purify methane
Implementation Method 3
exhaust gas oxidation catalyst for compressed natural gas combustion system
Data Source
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AI summary
Disclosed is a catalyst composition for inhibiting the deactivation of a catalyst for purifying exhaust gas from a compressed natural gas combustion system, which contains platinum and palladium as precious metal components. Specifically, a catalyst for purifying exhaust gas from a compressed natural gas vehicle or a static combustion system is configured such that a ceramic substrate is impregnated with palladium-impregnated first alumina, platinum-impregnated second alumina, and a ceria component, wherein the first alumina is further impregnated with a cocatalyst selected from the group consisting of barium, nickel, lanthanum, samarium, and yttrium, thus significantly inhibiting the deactivation of the CNG lean burn engine catalyst.