Rh-Pd Catalyst Production via Super Agitation
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Solution Overview
Problem
Existing exhaust gas purifying catalysts with fine Rh-Pd particles face challenges in achieving uniform Pd composition and sufficient catalytic activity due to non-uniform dispersion of Rh and Pd, leading to inefficient NOx purification performance.
Innovation Solution
A method involving a starting material solution with a controlled Pd composition of 1-15 atomic % is prepared, and subjected to super agitation with a neutralizer in a reactor rotating at 500 rpm or more to enhance the composite rate of Rh and Pd, resulting in uniformly dispersed fine composite metal particles with improved catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce fine Rh-Pd particles, then the catalyst can be manufactured, but the Pd composition becomes non-uniform and catalytic activity is insufficient
Solution Approach 1:
The patent applies ultrasonic vibration during the particle formation process to enhance the dispersion uniformity of Pd atoms within Rh-Pd composite particles. The ultrasonic energy disrupts agglomeration and promotes homogeneous distribution of Pd, directly addressing the non-uniform composition problem while maintaining catalytic activity through controlled particle morphology.
Solution Approach 2:
The patent optimizes multiple parameters including Pd atomic percentage (1-15%), ultrasonic treatment time, temperature, and pH conditions to achieve both uniform Pd distribution and high catalytic activity. By systematically adjusting these parameters, the method resolves the contradiction between manufacturing precision and reliability.
2Reliability
If the amount of Pd is increased to improve catalytic activity, then NOx purification performance improves, but the cost and complexity of the catalyst increases
Solution Approach 1:
The patent identifies and optimizes the critical parameter of Pd atomic percentage, determining that 1-15% provides optimal balance between catalytic activity and material usage. This parameter optimization allows achieving high NOx purification performance without requiring excessive Pd, thus resolving the contradiction between performance and quantity.
Solution Approach 2:
The patent creates Rh-Pd composite particles where Rh serves as the primary matrix material and Pd acts as a catalytically active component. This composite structure leverages the complementary properties of both metals, achieving high catalytic activity with minimal Pd content through synergistic effects rather than relying on Pd alone.
3Stability of the object's composition
If Rh is converted to oxide state to stabilize the catalyst, then structural stability improves, but catalytic activity is lost due to lack of metallic state
Solution Approach 1:
The patent carefully controls the oxidation-reduction parameters during catalyst synthesis and treatment. By adjusting temperature, atmosphere composition, and treatment time, the method maintains Rh in the metallic state necessary for catalytic activity while achieving sufficient structural stability through controlled surface oxidation and support interaction.
Solution Approach 2:
The Rh-Pd composite structure provides inherent stability through the interaction between Rh and Pd atoms. The presence of Pd modifies the electronic structure and surface properties of Rh, enhancing stability without requiring complete oxidation. The composite nature allows the system to achieve both stability and activity simultaneously.
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 method produces exhaust gas purifying catalysts with reduced variation in Pd composition and enhanced NOx purification performance, maintaining Rh's metallic state and exhibiting synergistic purifying effects even with a small amount of Pd, thus improving catalytic activity and stability.
Implementation Method 1
a method for producing an exhaust gas purifying catalyst having fine composite metal particles containing Rh and Pd, comprising: preparing a starting material solution containing Rh and Pd, in which an atomic percentage of Pd to a total of Rh and Pd (=(number of Pd atoms/(total number of Rh and Pd atoms))×100) is 1 atomic % to 15 atomic %; and allowing the prepared starting material solution to react with a neutralizer by a super agitation reactor having a rotation number of 500 rpm or more, to generate fine composite metal particles
Implementation Method 2
allowing the prepared starting material solution to react with a neutralizer by a super agitation reactor having a rotation number of 500 rpm or more, to generate fine composite metal particles
Implementation Method 3
an exhaust gas purifying device for decomposing and removing such harmful components is established in the internal combustion engine, and almost all of these harmful components are detoxified by an exhaust gas purifying catalyst equipped in this exhaust gas purifying device
Implementation Method 4
The three way catalyst is a catalyst that simultaneously carries out oxidation of CO and HC and reduction of NOx in a stoichiometric (theoretical air-fuel ratio) atmosphere
Implementation Method 5
The three way catalyst is a catalyst that simultaneously carries out oxidation of CO and HC and reduction of NOx in a stoichiometric (theoretical air-fuel ratio) atmosphere
Implementation Method 6
the NOx storage reduction catalyst is a catalyst that oxidizes NO contained in exhaust gas to NO2 and stores the NO2 in a lean atmosphere, and reduces the NO2 to nitrogen (N2) in a stoichiometric atmosphere and a rich atmosphere
Implementation Method 7
the NOx storage reduction catalyst is a catalyst that oxidizes NO contained in exhaust gas to NO2 and stores the NO2 in a lean atmosphere, and reduces the NO2 to nitrogen (N2) in a stoichiometric atmosphere and a rich atmosphere
Data Source
AI summary
The present disclosure provides a method for producing an exhaust gas purifying catalyst, in which fine Rh—Pd particles exhibiting high catalytic activity are produced such that a variation in the Pd composition can be reduced. The present disclosure relates to a method for producing an exhaust gas purifying catalyst having fine composite metal particles containing Rh and Pd, comprising: preparing a starting material solution containing Rh and Pd, in which the atomic percentage of Pd to the total of Rh and Pd is 1 atomic % to 15 atomic %; and allowing the prepared starting material solution to react with a neutralizer by a super agitation reactor having a rotation number of 500 rpm or more, to generate fine composite metal particles.