Zeolite Nanoparticle Encapsulation via In Situ Crystallization

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Solution Overview

Problem

Current methods for producing sinter-stable zeolite or zeotype encapsulated metal nanoparticles are time-consuming, expensive, and difficult to scale up for industrial applications, as they require specific zeolites with cages and complex procedures to control nanoparticle size and location.

Innovation Solution

A method involving treating a zeolite or zeolite-like structure with an alkaline solution and a surfactant, followed by heating to create additional porosity, impregnating with a transition metal precursor, and then subjecting it to a reactive atmosphere or thermal treatment to selectively form metal, metal oxide, or metal sulphide nanoparticles inside the zeolite structure, ensuring they are primarily positioned on internal surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If post-synthesis treatments are used to deposit nanoparticles inside zeolite cages, then nanoparticle formation is achieved, but the process becomes time-consuming and difficult to scale up

Engineering Contradiction:
Improvenanoparticle size and location controlVSAvoidproduction time and scalability
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by incorporating metal precursors into the zeolite structure during the crystallization process itself, rather than performing post-synthesis deposition. The metal salts are added to the synthesis mixture before crystallization, allowing nanoparticles to form in situ within the zeolite cages during the crystallization process, thereby eliminating time-consuming post-treatment steps while maintaining precise nanoparticle positioning.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges two separate processes into one: the zeolite crystallization process and the nanoparticle formation process. By combining these steps, the metal precursors are incorporated and transformed into nanoparticles simultaneously with zeolite crystal growth, achieving both zeolite synthesis and nanoparticle deposition in a single operation that is easier to scale up industrially.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If complex procedures are used to control nanoparticle size and location, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvenanoparticle positioning accuracyVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies self-service by utilizing the zeolite cage structure's inherent properties to automatically control nanoparticle size and location. The confined space of the zeolite cages naturally limits nanoparticle growth to specific sizes, and the cage positions automatically determine nanoparticle locations during crystallization, eliminating the need for complex external control mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent controls nanoparticle characteristics by adjusting synthesis parameters such as metal salt concentration, crystallization temperature, and pH conditions. By optimizing these parameters, the process achieves precise nanoparticle positioning and size control through simple parameter adjustments rather than complex procedural steps.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If metal nanoparticles are deposited on external surfaces, then deposition is achieved, but thermal stability and sintering resistance are reduced

Engineering Contradiction:
Improvenanoparticle deposition simplicityVSAvoidthermal stability and sintering resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies the nesting principle by placing metal nanoparticles inside the zeolite cage structures. The zeolite framework acts as a protective shell surrounding each nanoparticle, physically isolating them from each other and preventing sintering at elevated temperatures, while still allowing the simple impregnation-deposition manufacturing approach to remain effective.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 approach results in evenly distributed nanoparticles within the zeolite structure, enhancing thermal stability and catalytic activity while preventing sintering, thus creating a simple and scalable process for producing sintering-stable nanoparticle catalysts suitable for industrial use.

Implementation Method 1

treating a zeolite, zeolite-like or zeotype structure with an alkaline solution in the presence of a surfactant thereby obtaining a zeolite, zeolite-like or zeotype structure having a partly dissolved structure

Methodology Applied
Scientific EffectDissolution:

Implementation Method 2

heating the partly dissolved zeolite, zeolite-like or zeotype structure to an elevated temperature between 110-200 °C, thereby obtaining a zeolite, zeolite-like or zeotype structure with an additional porosity situated inside the structure

Methodology Applied
Scientific EffectThermal treatment: Heat Treatment

Implementation Method 3

impregnating the zeolite, zeolite-like or zeotype structure with the additional porosity situated inside the structure with a solution comprising at least one transition metal precursor

Methodology Applied
Scientific EffectImpregnation: Adsorption

Implementation Method 4

decomposing the transition metal precursor containing zeolite, zeolite-like or zeotype structure by thermal treatment

Methodology Applied
Scientific EffectThermal decomposition: Thermolysis

Implementation Method 5

subjecting the transition metal precursor containing zeolite, zeolite-like or zeotype structure to a reactive atmosphere selected from a stream of hydrogen gas (H2), a stream of oxygen gas (O2), a stream of hydrogen sulfide gas (H2S), a stream of methane gas (CH4), or a stream of ammonia gas (NH3) at an elevated temperature

Methodology Applied
Scientific EffectChemical reaction with reactive atmosphere: Chemical Bonding

Implementation Method 6

Encapsulation of metal nanoparticles in a zeolite structure may protect the individual nanoparticles from contact with other nanoparticles, thereby preventing sintering of the nanoparticles when these are subjected to elevated temperatures

Methodology Applied
Scientific EffectEncapsulation: Physical Containment

Data Source

PatentEP3129138B1A general method to incorporate metal nanoparticles in zeolites and zeotypes
Publication Date: 2020.07.01 DANMARKS TEKNISKE UNIV
  • EP3129138B1 patent drawingFigure 1
  • EP3129138B1 patent drawingFigure 2a~2b
  • EP3129138B1 patent drawingFigure 2c~2e

AI summary

Disclosed herein is a method for producing a zeolite, zeolite-like or zeotype structure with selective formation of metal, metal oxide or metal sulphide nanoparticles and/or clusters inside the zeolite, zeolite-like or zeotype structure.