SOMC Grafted Metal Oxide NH3-SCR Catalyst
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Solution Overview
Problem
Existing ammonia selective catalytic reduction (NH3-SCR) catalysts for nitrogen oxides (NOx) reduction exhibit low performance in terms of NOx conversion and N2 selectivity due to the formation of diversified species on the surface of support materials during conventional synthesis methods, leading to inefficient catalytic activity.
Innovation Solution
The Surface Organometallic Chemistry (SOMC) approach is used to graft organometallic precursors onto support materials like ceria and zirconia, forming chemical bonds that preserve the local structure and achieve atomic scale dispersion of metals, enhancing catalytic performance by promoting interaction between the metal and support material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional impregnation synthesis routes are used to prepare metal oxide catalysts, then the catalysts can be manufactured with simple processes, but the metal forms nanoparticles dispersed on support which results in low NOx conversion and low N2 selectivity
Solution Approach 1:
The support material surface is pre-modified with silane coupling agents before metal deposition, creating predetermined anchoring sites that control metal dispersion. This preliminary surface preparation ensures uniform metal distribution and prevents nanoparticle aggregation, achieving high manufacturing precision while maintaining relatively simple synthesis conditions
Solution Approach 2:
Silane coupling agents serve as intermediary substances between the support material and metal precursors. These intermediaries create stable surface complexes that control metal deposition, ensuring uniform dispersion at the molecular level rather than forming nanoparticles, thus resolving the contradiction between precise metal distribution and ease of manufacture
2Productivity
If metal is deposited on support surface by conventional impregnation, then the synthesis process is simple and fast, but diversified species form on the support surface leading to low catalytic activity
Solution Approach 1:
The support surface is divided into distinct functional zones: silane-modified regions that provide uniform anchoring sites for metal species, and unmodified regions that maintain the inherent support properties. This local differentiation ensures consistent metal dispersion and prevents formation of diversified species, achieving high catalytic reliability while maintaining efficient synthesis
Solution Approach 2:
The surface chemistry parameters of the support are modified by introducing silane coupling agents, changing the surface properties from hydroxyl-rich to silane-functionalized. This parameter change creates uniform binding sites that control metal species configuration, ensuring high catalytic activity and N2 selectivity without complicating the overall synthesis process
3Ease of manufacture
If nanoparticles of metal are dispersed on support, then the catalyst can be prepared by simple impregnation routes, but the catalytic performance shows low NOx conversion and low N2 selectivity
Solution Approach 1:
The support surface is pre-modified with silane coupling agents to create predetermined anchoring sites before metal deposition. This preliminary action ensures that metal species are deposited uniformly across the support surface at the molecular level, achieving high manufacturing precision while maintaining simple synthesis conditions
Solution Approach 2:
Silane coupling agents act as intermediary substances that mediate between the support material and metal precursors. They create stable surface complexes that control metal deposition, ensuring uniform dispersion at the molecular level rather than forming nanoparticles, thus resolving the contradiction between precise metal distribution and ease of manufacture
4Ease of manufacture
If diversified species are formed on support surface during conventional synthesis, then the synthesis process is straightforward, but the catalytic activity becomes inefficient
Solution Approach 1:
The support surface is divided into distinct functional zones: silane-modified regions that provide uniform anchoring sites for metal species, and unmodified regions that maintain the inherent support properties. This local differentiation ensures consistent metal dispersion and prevents formation of diversified species, achieving high catalytic reliability while maintaining efficient synthesis
Solution Approach 2:
The surface chemistry parameters of the support are modified by introducing silane coupling agents, changing the surface properties from hydroxyl-rich to silane-functionalized. This parameter change creates uniform binding sites that control metal species configuration, ensuring high catalytic activity and N2 selectivity without complicating the overall synthesis process
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
This method results in catalysts with significantly improved NOx conversion and selectivity in NH3-SCR reactions, achieving high NOx reduction performance compared to conventional catalysts, with catalysts showing nearly 100% NOx conversion over a wide range of temperatures.
Implementation Method 1
reacting the support material having surface hydroxyl (OH) groups with a silane coupling agent, thereby forming chemical bonds
Implementation Method 2
The Surface Organometallic Chemistry (SOMC) approach is used to graft organometallic precursors onto support materials like ceria and zirconia, forming chemical bonds
Implementation Method 3
ammonia selective catalytic reduction (NH3-SCR) catalysts for nitrogen oxides (NOx) reduction
Implementation Method 4
NH3 is adsorbed on a Brønsted acid site (V5+—OH) followed by N—H activation through the adjacent V═O surface groups through a redox cycle (V5=O/V4+—OH)
Implementation Method 5
NH3 is adsorbed on a Brønsted acid site (V5+—OH)
Data Source
AI summary
A process for preparing a catalyst material, includes: (a) providing a support material having surface hydroxyl (OH) groups, the support material is ceria (CeO2), zirconia (ZrO2) or a combination, and the support material contains between 0.3 and 2.0 mmol OH groups/g of the support material; (b) reacting the support material with at least one of: (b1) a compound containing at least one alkoxy or phenoxy group bound though its oxygen atom to a metal element from Group 5 (V, Nb, Ta) or Group 6 (Cr, Mo, W); (b2) a compound containing at least one hydrocarbon group bound though a carbon atom to a metal element from Group 5 or 6; (b3) a compound containing at least one hydrocarbon group bound though a carbon atom to a metal element which is copper (Cu); and (c) calcining the product obtained in step (b).