Laves Phase Intermetallic Catalyst for Ammonia Synthesis
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Solution Overview
Problem
Current ammonia synthesis catalysts using transition metals like ruthenium face challenges with high costs due to noble metal usage, hydrogen poisoning, and instability under reaction conditions, limiting catalytic activity and durability.
Innovation Solution
Development of a Laves phase intermetallic compound with a composition of ARu2, where A is Y, Sc, or other lanthanoid elements, with a crystallite size of 1-100 nm and a specific surface area of 0.5 m^2/g or more, which is produced using methods like arc melting and hydrogen adsorption-desorption treatment to enhance catalytic activity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ruthenium is used as a catalyst active component, then catalytic activity for ammonia synthesis is improved, but catalyst cost increases due to high price of noble metal
Solution Approach 1:
The patent replaces expensive noble metal ruthenium with a cheaper intermetallic compound system (rare earth metal + transition metal) that can be used in larger quantities at lower cost while maintaining catalytic activity for ammonia synthesis
Solution Approach 2:
The patent creates a composite intermetallic compound catalyst consisting of rare earth metal (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, or Sc) and transition metal (Fe, Co, or Ni) in a specific atomic ratio range, combining the benefits of both metal types to achieve high activity at lower cost
2Temperature
If transition metal catalyst is used, then reaction temperature and pressure can be reduced, but hydrogen poisoning occurs reducing catalytic activity
Solution Approach 1:
The patent creates a composite intermetallic compound where rare earth metal and transition metal (Fe, Co, or Ni) work synergistically - the transition metal provides catalytic activity while the rare earth metal component reduces hydrogen poisoning effects, enabling stable operation at lower temperatures and pressures
Solution Approach 2:
The patent optimizes the atomic ratio parameters of the intermetallic compound (transition metal/(rare earth metal + transition metal) between 0.3-0.7, and rare earth metal/(rare earth metal + transition metal) between 0.3-0.7) to achieve the optimal balance between catalytic activity and hydrogen poisoning resistance
3Stability of the object's composition
If intermetallic compound is used instead of simple metal catalyst, then catalyst stability is improved, but specific surface area decreases reducing catalytic activity
Solution Approach 1:
The patent optimizes the atomic ratio parameters and particle size of the intermetallic compound to achieve the optimal balance between stability and surface area - controlling particle size distribution and compositional parameters to maximize active surface area while maintaining the stable intermetallic phase structure
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 Laves phase intermetallic compound catalyst exhibits high catalytic activity, resistance to hydrogen poisoning, and durability, allowing for efficient ammonia synthesis at lower temperatures and pressures with reduced noble metal usage, thereby lowering production costs and improving reaction efficiency.
Implementation Method 1
a method for producing ammonia using the intermetallic compound... the Laves phase intermetallic compound catalyst exhibits high catalytic activity... allowing for efficient ammonia synthesis at lower temperatures and pressures
Implementation Method 2
hydrogen adsorption-desorption treatment to enhance catalytic activity and stability
Data Source
Figure 1~2
Figure 3A~3B
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AI summary
The invention provides a Laves phase intermetallic compound having a composition represented by general formula ARu2 (A is Y, Sc, or at least one element selected from lanthanoid elements excluding Ce), the crystallite size thereof being 1 nm to 100 nm; a catalyst including the intermetallic compound as an active ingredient; and a method for producing ammonia using the same.