ALD Oxide-Coated Palladium Catalyst for Biomass Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of adipic acid, a key component in nylon-6,6, faces challenges due to the susceptibility of platinum group metals like palladium to leaching, which hampers industrial scaling and increases costs, and activated carbon catalyst supports are prone to fouling during the hydrogenation of muconic acid.
Innovation Solution
The use of atomic layer deposition (ALD) to apply oxide coatings on palladium metal sites, stabilizing them against leaching and fouling, while maintaining accessibility, on various solid supports such as titanium dioxide and alumina, forming a hierarchical composite catalyst.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If platinum group metals like palladium are used as catalysts for hydrogenation, then catalytic activity is improved, but susceptibility to leaching increases
Solution Approach 1:
An oxide coating layer is introduced as an intermediary between the palladium metal and the reaction environment. This coating acts as a protective barrier that prevents direct contact between the metal and leaching agents, while still allowing catalytic function to occur. The oxide layer mediates between the need for high metal activity and the need for leaching resistance.
Solution Approach 2:
A thin oxide film is applied to the surface of the palladium particles. This thin film structure provides protection against leaching while maintaining sufficient porosity and surface area to allow reactant access to the underlying metal catalyst. The film thickness is optimized to balance protection with catalytic accessibility.
2Ease of manufacture
If activated carbon catalyst supports are used, then cost is reduced, but susceptibility to fouling increases
Solution Approach 1:
The oxide coating is applied with controlled porosity that allows reactant molecules to diffuse through to the metal surface while preventing larger fouling species from accessing and blocking the catalyst sites. The porous structure of the oxide layer acts as a molecular sieve that filters out fouling compounds.
Solution Approach 2:
The catalyst is designed as a composite structure combining activated carbon support, metal particles, and oxide coating. This composite approach leverages the low cost of activated carbon while adding protective and anti-fouling properties through the oxide layer, creating a material that combines multiple functions.
3Reliability
If oxide coating is applied to protect metal, then resistance to leaching is improved, but accessibility to metal may be reduced
Solution Approach 1:
The oxide coating is designed with a porous structure that provides pathways for reactant molecules to reach the metal surface. The porosity allows diffusion of hydrogen and muconic acid through the oxide layer to the catalytic sites, maintaining high accessibility while the oxide framework continues to provide leaching protection.
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 reduced palladium leaching and improved stability, maintaining high catalytic activity and selectivity, even after exposure to muconic acid, thus overcoming the limitations of conventional catalysts.
Implementation Method 1
The use of atomic layer deposition (ALD) to apply oxide coatings on palladium metal sites, stabilizing them against leaching and fouling
Implementation Method 2
Muconic acid can be hydrogenated in the condensed phase over platinum group metals
Implementation Method 3
stabilizing them against leaching and fouling
Data Source
AI summary
The present disclosure relates to a composition that includes a solid support, a metal positioned on the solid support, and an oxide coating positioned to at least partially cover the metal. The compositions described herein may be utilized in methods that include contacting muconic acid and hydrogen to convert at least a portion of the muconic acid to adipic acid.