Ru-Ba-A Core-Shell Catalyst for Ammonia Synthesis
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Solution Overview
Problem
Ruthenium-based catalysts for ammonia synthesis exhibit poor stability and low catalytic performance, particularly in coal gas systems, due to the small contacting area between ruthenium nanoparticles and metal oxides, leading to agglomeration and reduced activity.
Innovation Solution
A ruthenium-based catalyst with a Ru—Ba-A core-shell structure, where ruthenium nanoparticles are coated with barium nanoparticles and metal oxides, preventing agglomeration and direct contact with water vapor, and utilizing a composite support with an electron promoter to enhance stability and activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ruthenium nanoparticles are highly dispersed on activated carbon support, then ruthenium utilization rate is improved, but catalyst stability and catalytic performance deteriorate
Solution Approach 1:
The patent applies a core-shell structure where ruthenium nanoparticles form the core, barium oxide forms an intermediate layer, and metal oxide forms the outer shell. This nested multi-layer structure prevents direct contact between ruthenium and water vapor while maintaining high dispersion of ruthenium on the support, thereby achieving both high utilization rate and improved stability
Solution Approach 2:
The patent introduces barium oxide as an intermediary layer between the ruthenium core and the external environment. This intermediate layer acts as a protective barrier that prevents water vapor from directly contacting the ruthenium nanoparticles, thus improving catalyst stability without affecting the ruthenium utilization rate
2Productivity
If ruthenium nanoparticles contact metal oxides directly, then catalytic activity is improved, but nanoparticle agglomeration occurs and stability deteriorates
Solution Approach 1:
The patent creates a nested structure where the ruthenium core is surrounded by barium oxide intermediate layer and metal oxide outer shell. This arrangement maintains the necessary contact between ruthenium and metal oxide for catalytic activity while preventing direct aggregation of ruthenium nanoparticles, thus achieving both high catalytic activity and nanoparticle stability
3Productivity
If catalyst is used in coal gas synthesis system, then ammonia production is achieved, but catalyst stability and performance deteriorate due to water vapor interaction
Solution Approach 1:
The patent introduces barium oxide as an intermediary protective layer between the ruthenium catalyst and water vapor in the coal gas system. This intermediate layer prevents harmful interactions with water vapor that would otherwise reduce catalyst stability, while allowing the catalyst to maintain its ammonia production capability
Solution Approach 2:
The multi-layer nested structure (ruthenium core, barium oxide intermediate layer, metal oxide outer shell) protects the ruthenium catalyst from water vapor in the coal gas synthesis system, enabling sustained ammonia production with improved catalyst stability and performance
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 core-shell structure effectively prevents ruthenium nanoparticle agglomeration and reduces interactions with water vapor, improving catalytic performance and stability, and the specific composition and preparation method enhance the anti-methanization ability and long cycle life of the catalyst.
Implementation Method 1
a ruthenium nanoparticle as a core which is covered with a first shell and a second shell sequentially, wherein the first shell consists of a barium nanoparticle
Implementation Method 2
the first shell consists of a barium nanoparticle, and the second shell consists of a metal oxide
Implementation Method 3
a composite support which comprises a support member having an electron promoter dispersed on a surface of the support member
Data Source
AI summary
Disclosed is a ruthenium-based catalyst for ammonia synthesis, preparation method and use thereof. The ruthenium-based catalyst comprises Ru—Ba-A core-shell structure which comprises a ruthenium nanoparticle as a core covered with a first shell and a second shell sequentially, wherein the first shell consists of a barium nanoparticle, and the second shell consists of a metal oxide. The Ru—Ba-A core-shell structure can effectively preventing agglomerations of ruthenium nanoparticles during the use of the catalyst and avoiding direct contact between the ruthenium nanoparticles and the metal oxides. In addition, barium nanoparticles have a promoting effect as an electronic promoter, which can effectively improve the stability and catalytic activity of ruthenium-based catalyst for ammonia synthesis, especially in the system for synthesizing ammonia from a coal gas.