Cu-P Co-Supported Zeolite for SCR Catalyst Thermal Endurance
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Solution Overview
Problem
Current methods struggle to synthesize zeolites with low silica-alumina ratios that can effectively support catalytic metals, particularly copper, while maintaining high thermal endurance and sufficient ion exchange capacity, especially in small pore zeolites like CHA-type zeolites, due to limitations in phosphorus incorporation and high production costs.
Innovation Solution
A Cu—P co-supported zeolite is developed with extra-backbone copper and phosphorus atoms supported on small pore size zeolites, featuring a silica-alumina ratio between 7 and 20, specific atomic ratios, and a novel composition that allows for efficient co-supporting of copper and phosphorus, enhancing thermal endurance and catalyst performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If phosphoric acid is used for post-treatment of zeolite to increase heat resistance and catalytic activity, then thermal endurance is improved, but phosphoric acid cannot penetrate into pores of small pore zeolites due to molecular size limitation
Solution Approach 1:
The patent changes the physical state and molecular size parameters of phosphorus compounds by using alternatives to phosphoric acid, such as ammonium phosphates and phosphonics, which have smaller molecular dimensions that can penetrate the 3.8 Å pores of CHA-type zeolites while still providing the desired heat resistance and catalytic activity enhancement
Solution Approach 2:
The patent uses ammonium phosphates and phosphonics as intermediary compounds that can access the zeolite pores and deliver phosphorus to the active sites. These intermediaries decompose or transform within the pores to provide the desired phosphorus modification without requiring direct phosphoric acid penetration
2Reliability
If phosphorus is introduced into CHA backbone by synthesizing phosphorus T-atom-containing low-phosphorus molecular sieve, then hydrothermal stability is increased, but production cost increases and synthesis complexity increases
Solution Approach 1:
The patent applies post-synthesis treatment methods where phosphorus compounds are applied to pre-formed CHA-type zeolites. This preliminary formation of the zeolite structure followed by phosphorus impregnation simplifies the overall synthesis process compared to attempting to incorporate phosphorus during the crystallization phase, while still achieving the desired hydrothermal stability
Solution Approach 2:
The patent employs commercially available ammonium phosphate salts and phosphonic acids that can be easily procured and applied in simple impregnation procedures. These readily available compounds provide cost-effective phosphorus sources compared to specialized phosphorus-containing precursors required for in-situ synthesis
3Productivity
If copper is supported on zeolite for selective catalytic reduction, then nitrogen oxide purification is achieved, but ion exchange capacity is insufficient when silica-alumina ratio is low
Solution Approach 1:
The patent applies phosphorus treatment locally at the copper active sites and pore surfaces of the zeolite. This localized phosphorus modification enhances the copper-nitrogen oxide interaction and stabilizes the copper species without requiring uniform phosphorus distribution throughout the entire zeolite structure, thereby maintaining high ion exchange capacity even at low silica-alumina ratios
Solution Approach 2:
The patent creates a composite structure combining copper species, phosphorus compounds, and CHA-type zeolite. This composite material synergistically integrates the nitrogen oxide reduction capability of copper with the hydrothermal stability and structural integrity provided by phosphorus-modified zeolite, achieving effective catalysis at low silica-alumina ratios
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 Cu—P co-supported zeolite achieves excellent thermal endurance and catalyst performance, enabling effective nitrogen oxide purification even under harsh conditions, with improved production costs and processes compared to conventional methods.
Implementation Method 1
Copper-promoted zeolite beta is one of the effective catalysts for selective reduction of nitrogen oxide with ammonia
Implementation Method 2
calcinating after protecting Al sites that have relatively low heat resistance improve heat resistance
Data Source
AI summary
Provided are a high-performance Cu—P co-supported zeolite and the like having excellent thermal endurance and catalyst performance. A Cu—P co-supported zeolite comprising at least a small pore size zeolite, and an extra-backbone copper atom and an extra-backbone phosphorus atom supported on the small pore size zeolite, wherein a silica-alumina ratio (SiO2/Al2O3) is 7 or more and 20 or less, a ratio of the copper atom to a T atom (Cu/T) is 0.005 or more and 0.060 or less, a ratio of the phosphorus atom to the T atom (P/T) is 0.005 or more and 0.060 or less, and a ratio of the phosphorus atom to the copper atom (P/Cu) is 0.1 or more and 3 or less.