Composite Catalyst for NOx Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current catalysts for selective catalytic reduction of NOx in automotive exhaust gases are inefficient, especially at high temperatures and after aging, and require high catalytic metal loading, necessitating the development of more active and cost-effective materials that outperform traditional copper chabazite and iron zeolite beta.
Innovation Solution
A composite catalyst comprising an amorphous mesoporous metal and/or metalloid oxide combined with a zeolitic material containing a metal as a non-framework element, prepared through a process involving a metal-organic framework material, a zeolitic material, a solvent system, and a pasting agent, followed by calcination, to enhance NOx conversion activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional copper chabazite and iron zeolite beta catalysts are used, then NOx reduction function is provided, but catalytic activity deteriorates at high temperatures and after aging
Solution Approach 1:
The patent employs a composite catalyst material combining amorphous mesoporous metal/metalloid oxide with crystalline zeolitic material. This composite structure integrates the high-temperature stability of crystalline zeolites with the high catalytic activity of amorphous metal oxides, resolving the contradiction between catalyst stability and NOx conversion activity. The amorphous phase provides active sites for NOx reduction while the crystalline zeolite framework maintains structural integrity at high temperatures and during aging.
2Productivity
If high catalytic metal loading is used, then NOx conversion activity is improved, but production cost increases
Solution Approach 1:
The patent utilizes amorphous mesoporous metal and/or metalloid oxide as the catalytic active phase. The mesoporous structure provides high surface area and numerous active sites, enabling high NOx conversion activity with reduced metal loading compared to traditional catalysts. The porous architecture allows efficient diffusion of reactants to active sites and products away, maintaining high productivity without requiring excessive metal content.
3Productivity
If amorphous mesoporous metal oxide is combined with zeolitic material, then NOx conversion activity at high temperature is improved, but catalyst preparation complexity increases
Solution Approach 1:
The patent employs a two-stage preparation process where the amorphous mesoporous metal/metalloid oxide is first synthesized and dried, then mixed with zeolitic material and subjected to calcination. This preliminary preparation of the amorphous phase before combination with zeolite simplifies the overall process by allowing separate optimization of each component's structure and properties, while still achieving synergistic effects in the final composite catalyst.
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 composite catalyst exhibits improved NOx conversion activity at high temperatures and maintains performance after aging, achieving levels comparable to benchmark catalysts with reduced metal loading and lower production costs.
Implementation Method 1
a catalyst comprising a composite material containing an amorphous mesoporous metal and/or metalloid oxide and a zeolitic material
Implementation Method 2
zeolitic material containing a metal as non-framework element
Data Source
AI summary
The present invention relates to a process for the preparation of a catalyst for selective catalytic reduction comprising • (i) preparing a mixture comprising a metal-organic framework material comprising an ion of a metal or metalloid selected from groups 2-5, groups 7-9, and groups 11-14 of the Periodic Table of the Elements, and at least one at least monodentate organic compound, a zeolitic material containing a metal as a non-framework element, optionally a solvent system, and optionally a pasting agent, • (ii) calcining of the mixture obtained in (i); and further relates to a catalyst per se comprising a composite material containing an amorphous mesoporous metal and/or metalloid oxide and a zeolitic material, wherein the zeolitic material contains a metal as non-framework element, as well as to the use of said catalyst.