ALD Overcoated Dehydrogenation Catalyst for Sintering Resistance
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Solution Overview
Problem
Existing platinum-based alkane dehydrogenation catalysts suffer from sintering at high temperatures, leading to reduced activity and selectivity for propylene production, which is not adequately addressed by conventional overcoatings that compromise catalytic performance.
Innovation Solution
A method involving calcining a catalyst support, impregnating it with nanoparticle precursors, and applying an atomic layer deposition (ALD) overcoat to form an alkane dehydrogenation catalyst, which includes a thin ALD overcoat to protect catalytic nanoparticles, maintaining their activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional overcoating is applied to protect platinum nanoparticles from sintering, then sintering resistance is improved, but catalytic activity is reduced
Solution Approach 1:
The patent applies a thin overcoat layer (1-5 nm) that provides sintering protection only where needed on the nanoparticle surface, rather than complete coverage. This localized protection maintains most catalytic active sites exposed while preventing nanoparticle aggregation, resolving the contradiction between sintering resistance and catalytic activity.
Solution Approach 2:
The patent changes the thickness parameter of the overcoat layer to an optimized range (1-5 nm) that balances protection and activity. This parameter optimization allows the overcoat to be thick enough to prevent sintering but thin enough to maintain catalytic activity, directly resolving the technical contradiction.
2Productivity
If high reaction temperature is used to maintain dehydrogenation performance, then propylene selectivity is improved, but sintering of platinum nanoparticles occurs
Solution Approach 1:
The patent applies an overcoat layer before high-temperature operation to preemptively protect the platinum nanoparticles from sintering. This preliminary protective action allows the catalyst to withstand high reaction temperatures (above 600°C) that maintain propylene selectivity without suffering from nanoparticle aggregation and deactivation.
Solution Approach 2:
The patent converts the harmful effect of high temperature (which causes sintering) into a beneficial operating condition by using the overcoat as a thermal barrier. The same high temperature that would normally harm the nanoparticles is now tolerated because the overcoat protects them, allowing the system to operate at temperatures optimal for propylene selectivity.
3Productivity
If frequent regeneration under chlorine atmosphere is performed to re-disperse platinum nanoparticles, then catalytic activity is restored, but process complexity and operational time increase
Solution Approach 1:
The patent applies an overcoat layer in advance that prevents nanoparticle sintering from occurring in the first place, eliminating the need for frequent regeneration operations. This preliminary protective measure avoids the complexity of chlorine-based regeneration processes while maintaining continuous catalytic activity.
Solution Approach 2:
The patent extracts and removes the need for complex regeneration operations by using the overcoat to prevent sintering permanently. Instead of periodically restoring activity through chlorine treatment, the overcoat provides continuous protection, eliminating the regeneration step entirely and simplifying the overall process.
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 ALD-coated catalysts demonstrate improved resistance to sintering, maintaining catalytic activity and selectivity towards alkenes, even after prolonged steam treatments at high temperatures, with alkane conversion rates and alkene selectivity exceeding conventional methods.
Implementation Method 1
depositing by atomic layer deposition (ALD) the overcoat onto the calcined catalyst precursor by contacting the calcined catalyst precursor with an ALD precursor and water
Implementation Method 2
calcining the impregnated catalyst precursor under conditions sufficient to convert the nanoparticle precursor impregnated in the impregnated catalyst precursor to catalytic nanoparticles
Implementation Method 3
annealing the catalyst intermediate in air at a temperature of less than about 600° C. for about 30 minutes to about 2 hours
Data Source
AI summary
Provided herein is an alkane dehydrogenation catalyst, a method of manufacturing an alkane dehydrogenation catalyst, and a method of converting alkanes to alkenes.