Ammonia Synthesis Catalyst with Metal Hydride-Nitride Composite
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Solution Overview
Problem
Existing ammonia synthesis catalysts require high temperatures and pressures, making them inefficient for green ammonia applications with intermittent energy sources, and are also costly and energy-intensive to produce.
Innovation Solution
A solid material comprising a metal selected from Fe, Co, Ni, Mo, Ru, V, Mn, supported on an oxide of Ti, Si, Ce, Al, Zr, La, Eu, Pr, or Nb, combined with a hydride of an alkali or alkaline-earth metal and a nitride, specifically designed to enhance catalytic activity at lower temperatures and pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional Fe-based catalysts are used for ammonia synthesis, then the catalyst can operate at industrial conditions, but it requires high temperatures (400-500 °C) and high pressures (150-300 bar)
Solution Approach 1:
The patent uses composite materials by combining metal nanoparticles (Fe, Co, Ni, Mo, Ru, V, or Mn) dispersed on oxide supports (TiO2, SiO2, CeO2, Al2O3, ZrO2, La2O3, Eu2O3, Pr2O3, or Nb2O5) with alkali metal or alkaline-earth metal hydrides and nitrides. This composite structure enables the catalyst to achieve high catalytic activity at lower temperatures and pressures compared to conventional Fe-based catalysts, resolving the contradiction between operating conditions and catalytic performance.
Solution Approach 2:
The patent changes the chemical and physical parameters of the catalyst by incorporating hydrides and nitrides of alkali or alkaline-earth metals alongside the metal-support composite. This parameter modification allows the catalyst to function effectively at reduced temperatures and pressures while maintaining or enhancing ammonia synthesis activity, thus resolving the technical contradiction.
2Temperature
If Ru-based catalysts are used to operate at milder conditions, then the operating temperature and pressure are reduced, but the manufacturing cost increases
Solution Approach 1:
The patent employs inexpensive metal nanoparticles (particularly Fe, Co, Ni, and Mn) as alternatives to expensive Ru-based catalysts. By using these cheaper metals in combination with oxide supports and hydride-nitride additives, the catalyst achieves comparable or superior performance at lower operating conditions without the high manufacturing cost associated with ruthenium, thus resolving the contradiction between mild operating conditions and manufacturing cost.
Solution Approach 2:
The composite structure of metal/oxide with hydride-nitride components enables cheaper metals to achieve the catalytic performance previously only attainable with expensive Ru-based catalysts, making the system both cost-effective and energy-efficient.
3Ease of manufacture
If supported catalysts are used to reduce manufacturing cost and increase dispersion, then the cost is reduced and dispersion is improved, but the energy intensity for production remains high
Solution Approach 1:
The patent employs preliminary action by pre-synthesizing the oxide supports and metal nanoparticles separately, then combining them with hydrides and nitrides through a simple mixing process. This preliminary preparation allows the final catalyst to be assembled with minimal energy input, avoiding high-energy synthesis steps while maintaining cost-effectiveness and dispersion benefits.
Solution Approach 2:
The catalyst is segmented into distinct functional components (metal nanoparticles, oxide support, hydride additive, nitride additive) that are prepared separately and then combined. This segmentation allows each component to be optimized independently and assembled with low energy input, resolving the contradiction between manufacturing cost and energy intensity.
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 solid material exhibits improved catalytic activity for ammonia synthesis at lower temperatures and pressures, is less expensive and energy-intensive to produce, and maintains on-stream stability and resistance to sintering.
Implementation Method 1
The solid material exhibits improved catalytic activity for ammonia synthesis at lower temperatures and pressures
Implementation Method 2
These activations typically involve electronic transfer reactions promoted by the high temperature and the presence of promoters with electrondonating properties
Implementation Method 3
the activation of molecular nitrogen to form reactive atomic species. These activations typically involve electronic transfer reactions
Implementation Method 4
the presence of promoters with electrondonating properties
Data Source
Figure 1(a)~1(b)
Figure 1(c)~2
Figure 3(a)~3(b)
AI summary
A solid material comprising or, alternatively, consisting of: (i) at least one metal selected from among Fe, Co, Ni, Mo, Ru, V, Mn; (ii) at least a support for said at least one metal (i), said support being an oxide of Ti, Si, Ce, Al, Zr, La, Eu, Pr or Nb; (iii) at least a hydride of an alcali metal or an alcali-earth metal; (iv) at least a nitride. A use of said solid material as a catalyst, and a process for the preparation of a solid material are also disclosed.