Single Atom Catalyst Dispersion via Porous Support Segmentation
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Solution Overview
Problem
Traditional catalyst formation methods result in inefficient use of precious metal catalysts due to agglomeration and stacking, leading to a significant portion of catalyst atoms being unavailable for reaction, increasing costs and reducing catalytic activity.
Innovation Solution
A process is developed to achieve single atom dispersion of catalysts on a porous substrate by preparing a solution with a promoter of opposite charge, adjusting pH, immersing and drying the substrate, and calcining under elevated temperatures, which allows for effective dispersion measurement using hydrogen-oxygen titration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional catalyst formation methods are used with incremental metal loading, then catalyst structure is formed, but metal atoms agglomerate and stack resulting in poor dispersion and reduced catalytic activity
Solution Approach 1:
The patent introduces a porous support material as an intermediary carrier for the metal catalyst. The support provides a large surface area with controlled porosity that prevents metal atom agglomeration while enabling uniform distribution. This intermediary structure allows the metal to be dispersed at the atomic level without direct metal-metal contact that would cause stacking.
Solution Approach 2:
The patent utilizes porous support materials with specific pore size distributions to achieve high catalyst dispersion. The porous structure provides numerous anchoring sites for metal atoms while the pore confinement effect prevents agglomeration. The hierarchical porosity enables both high surface area for dispersion and controlled mass transport for catalytic activity.
2Quantity of substance
If metal loading is increased to enhance catalytic activity, then more catalyst atoms are available, but agglomeration increases resulting in lower fraction of active atoms
Solution Approach 1:
The patent applies local quality by creating regions of high metal concentration within pores while maintaining overall low bulk concentration. The metal is distributed non-uniformly at the nanoscale - concentrated at specific anchoring sites within pores rather than uniformly throughout the catalyst bed. This local concentration strategy maximizes atom utilization while preventing bulk agglomeration.
Solution Approach 2:
The patent transitions from two-dimensional surface loading to three-dimensional pore-filling dispersion. Instead of loading metal on the external surface, the metal atoms are distributed throughout the three-dimensional pore network of the support. This dimensional transition provides vastly increased surface area and prevents agglomeration by confining atoms within pore structures.
3Device complexity
If catalyst atoms are stacked or agglomerated, then catalyst structure is simplified, but a portion of atoms becomes unavailable for reaction increasing costs
Solution Approach 1:
The patent segments the catalyst into individual atomic units dispersed throughout the porous support rather than forming continuous metal structures. Each metal atom acts as an independent catalytic site, preventing the formation of inactive bulk regions. This segmentation strategy ensures that every atom contributes to catalytic activity while avoiding the simplification that leads to agglomeration.
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 increases catalyst activity by up to three orders of magnitude, achieving greater than 90% dispersion of catalyst atoms, reducing costs, and enhancing electrochemical reactions and catalyst efficiency.
Implementation Method 1
the solution contains an atom or molecule having an opposite charge from Pt precursor to prevent Pt agglomeration during the impregnation of the porous catalyst support with the Pt catalyst
Implementation Method 2
immersing the porous material in the solution
Implementation Method 3
drying the porous solution under conditions that prevents capillary effect transfer from an interior of the support to an exterior of the support
Implementation Method 4
performing a catalyst calcination step under elevated temperatures of between 450° and 700° C. and in the presence of an inert gas
Implementation Method 5
reducing the catalyst under elevated temperatures and in the presence of a reducing agent such as hydrogen
Data Source
AI summary
Supported catalysts having an atomic level single atom structure are provided such that substantially all the catalyst is available for catalytic function. Processes of forming a catalyst unto a porous catalyst support is also provided.