Hierarchically Ordered Crystalline Materials for Controlled Mesoporosity
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Solution Overview
Problem
Conventional methods for synthesizing hierarchically ordered crystalline materials, such as zeolites, often result in limited long-range ordering of mesophases, random mesopore sizes and locations, and lack control over the silica-to-alumina ratio (SAR), leading to poorly interconnected mesopores and inefficient diffusion of larger species.
Innovation Solution
A method involving the formation of an aqueous suspension with a parent crystalline microporous material, an alkaline reagent, a supramolecular template, and a silica or alumina source, followed by hydrothermal treatment, to induce controlled dissolution and self-assembly, resulting in hierarchically ordered crystalline materials with improved mesoporosity and SAR control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form hierarchically ordered crystalline materials, then the microporous structure is maintained, but the long-range ordering of mesophase is limited and mesopores are random in size and location
Solution Approach 1:
The patent uses supramolecular templates as intermediary structures that self-assemble into ordered mesophases, which then guide the formation of hierarchically ordered crystalline materials. These templates act as mediators between the microporous parent material and the desired mesoporous structure, enabling long-range ordering without requiring complex external control mechanisms.
Solution Approach 2:
The method employs self-assembly of supramolecular templates and controlled dissolution of parent material to automatically generate the hierarchically ordered structure. The system uses thermodynamic driving forces and molecular recognition to spontaneously organize into the desired hierarchical architecture, eliminating the need for complex external directing agents or multi-step processing.
2Manufacturing precision
If post-synthetic modification strategies are used, then hierarchically ordered structures can be formed, but control over silica-to-alumina ratio is lost and dissolution process is poorly controlled
Solution Approach 1:
The patent incorporates silica and alumina source materials into the aqueous suspension before hydrothermal treatment, allowing preliminary control of the silica-to-alumina ratio in the reaction mixture. This preliminary action ensures that the desired SAR is established before the dissolution and crystallization processes begin, maintaining precision throughout the transformation.
Solution Approach 2:
The method controls the dissolution process by adjusting parameters such as pH, temperature, and composition of the aqueous suspension. By carefully controlling these parameters during hydrothermal treatment, the patent achieves both controlled dissolution of parent material and precise control over the final silica-to-alumina ratio in the hierarchically ordered product.
3Productivity
If mesopores are introduced to improve diffusion of larger species, then accessibility to active sites improves, but mesopores become poorly interconnected
Solution Approach 1:
The patent creates a nested hierarchical structure where ordered mesopores are embedded within the microporous crystalline framework. The supramolecular templates self-assemble to form mesoporous channels that are intimately connected to the microporous active sites, creating a nested architecture that ensures efficient mass transport from meso- to micropores while maintaining structural integrity.
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 method produces crystalline materials with enhanced mesoporosity and controlled SAR, enabling better diffusion of larger species and improved catalytic performance by maintaining the integrity of the microporous structure while achieving well-defined mesoporous symmetry.
Implementation Method 1
the inclusion of the alkaline reagent and the supramolecular template in the method may induce dissolution of the parent crystalline microporous material
Implementation Method 2
induce dissolution of the parent crystalline microporous material and self-assembly to produce the hierarchically ordered crystalline material
Implementation Method 3
hydrothermally treating the aqueous suspension to form the hierarchically ordered crystalline microporous material
Data Source
AI summary
Methods of making hierarchically ordered crystalline microporous materials are provided. The method may include forming an aqueous suspension comprising a parent crystalline microporous material, an alkaline reagent, a supramolecular template, and a silica source material, an alumina source material, or both. The method may further include hydrothermally treating the aqueous suspension to form the hierarchically ordered crystalline microporous material. The hierarchically ordered crystalline material may have a greater degree of mesoporosity than the parent crystalline microporous material and may have a silica-to-alumina ratio (SAR) that is at least 0.5 different than the parent crystalline microporous material.