Multimetallic Oxide NOx Sorbent for Cost-Effective Emission Control
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Solution Overview
Problem
Current NOx adsorber systems, particularly those using noble metal/zeolite catalysts, face high costs and limited practical application due to the expense of noble metals, necessitating a more affordable and efficient PGM-free NOx sorbent material with higher storage capacity for reducing emissions in exhaust systems.
Innovation Solution
A multimetallic oxide NOx sorbent material comprising alkali or alkaline earth metals, 3d transition metals, and rare-earth elements, with a manganese catalyst as a promoter, supported on high surface area materials like inorganic oxides or zeolites, designed to adsorb NOx at low temperatures and release it at higher temperatures, effectively utilizing manganese compounds and additives for enhanced NOx storage and conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noble metal/zeolite catalysts are used for NOx adsorption, then NOx storage capacity and conversion are improved, but cost increases significantly
Solution Approach 1:
The patent replaces expensive noble metals with inexpensive alternative metals such as Fe, Co, Ni, Cu, and Mn that can be easily deposited on zeolite supports. These non-noble metals provide sufficient NOx storage and conversion performance without the high cost associated with Pt, Pd, Rh, and Ru catalysts, making the system economically viable for widespread application.
Solution Approach 2:
The patent creates composite catalyst materials by combining non-noble metals with zeolite supports and promoting them with alkali metals (Na, K, Cs). This composite structure leverages the high surface area and porosity of zeolites together with the catalytic activity of transition metals and the promotional effect of alkali metals, achieving noble metal-free NOx treatment performance.
2Ease of manufacture
If PGM-free NOx sorbent material is developed, then cost is reduced, but NOx storage capacity may be limited
Solution Approach 1:
The patent modifies the chemical composition parameters of the catalyst by incorporating specific ratios of transition metals (Fe, Co, Ni, Cu, Mn) and alkali metal promoters (Na, K, Cs) on zeolite supports. By optimizing these compositional parameters, the catalyst achieves high NOx storage capacity comparable to or exceeding PGM-based systems while maintaining cost-effectiveness.
Solution Approach 2:
The patent utilizes zeolite supports with high surface area and controlled pore structures to maximize the dispersion and accessibility of non-noble metal catalysts. The porous nature of zeolites provides extensive active sites for NOx adsorption and reaction, compensating for the lower intrinsic activity of non-noble metals compared to noble metals.
3Quantity of substance
If multimetallic oxide composition is used, then NOx storage capacity is enhanced, but material complexity increases
Solution Approach 1:
The patent divides the catalyst into distinct functional components: zeolite support providing physical structure and surface area, transition metals providing catalytic activity, and alkali metal promoters enhancing performance. This segmentation allows each component to be optimized independently while working synergistically, managing complexity through functional decomposition.
Solution Approach 2:
The patent develops a universal catalyst formulation that can be applied across different engine types and operating conditions using the same basic composition of transition metals, alkali metal promoters, and zeolite supports. This multi-functional approach handles various NOx emission scenarios (cold start, warmed-up, different load conditions) with a single versatile catalyst design, reducing overall system complexity.
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 NOx sorbent material effectively absorbs NOx at temperatures below 350°C and releases it at temperatures above, demonstrating improved NOx storage and conversion capabilities compared to PGM-based systems, suitable for various engine types and operating conditions, including cold starts and warmed-up operations.
Implementation Method 1
The NOx sorbent material is configured to adsorb and absorb NOx at or below a low temperature
Implementation Method 2
released when at a high temperature
Data Source
AI summary
A Nitrogen Oxide (NOx) sorbent material of the present invention includes a multi-metallic oxide that includes one or more alkali or alkaline earth metal, one or more 3d transition metal, and one or more rare earth element. The NOx sorbent material is configured to adsorb and absorb NOx below a low temperature and to release the adsorbed or absorbed NOx at temperature at or above the low temperature. In some embodiments, a manganese catalyst is deposited on a high surface area carrier. The manganese catalyst takes the form of an alkali/metal promotor and an Mn-based compound. In general, the NOx sorbent material contains about one percent to about fifty percent by weight of alkali/alkaline earth metal manganese catalyst based on the total weight of the catalyst.