Subnanometer Catalyst Clusters for Water Splitting
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Solution Overview
Problem
Current electrocatalysts for water oxidation reactions require high overpotentials, are inefficient, and rely heavily on expensive precious metals, leading to high energy consumption and catalyst degradation, with macro-sized materials being ill-defined and unstable.
Innovation Solution
The use of size-selected catalyst clusters with no more than 50 atoms, supported on conductive substrates, covering a small percentage of the surface, to enhance catalytic efficiency and longevity, and the development of self-healing systems that minimize precious metal usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If macro-sized catalyst particles (>5 nm) are used, then catalyst stability is improved, but catalytic efficiency and turnover rates deteriorate
Solution Approach 1:
The patent changes the size parameter of catalyst particles from macro-sized (>5 nm) to subnanometer clusters (≤5 nm, preferably 1-3 nm). This parameter change increases the surface-to-volume ratio, exposing more active sites and improving turnover rates while maintaining stability through controlled cluster formation and support interactions.
Solution Approach 2:
The patent segments macro-sized particles into smaller subnanometer clusters. This segmentation increases the number of surface atoms available for catalysis while maintaining structural integrity through controlled dispersion on support materials, thereby improving both efficiency and stability.
2Area of stationary object
If high metal/metal oxide loadings are used, then catalyst coverage is improved, but cost and material waste increase
Solution Approach 1:
The patent applies local quality by creating non-uniform distributions of metal species, concentrating catalytic activity at specific sites (subnanometer clusters) rather than uniform macro-sized particles. This allows high coverage with minimal material, as only the cluster surfaces are active, reducing bulk material waste.
Solution Approach 2:
The patent extracts only the necessary amount of precious metal to form subnanometer clusters, removing the need for high bulk loadings. The clusters are dispersed on support materials, allowing high surface coverage with minimal metal content, thus reducing material waste and cost.
3Productivity
If precious metals are used, then catalytic activity is improved, but cost increases
Solution Approach 1:
The patent changes the size parameter to subnanometer scales where quantum effects and surface atom dominance enhance catalytic activity per atom. This allows using fewer precious metal atoms (reducing cost) while maintaining or improving activity through higher surface-to-volume ratios and optimized electronic structures.
Solution Approach 2:
The patent replaces expensive precious metals with cheaper alternative metals or metal oxides in subnanometer cluster forms. The high surface area and reactivity of these small clusters compensate for the lower intrinsic activity of non-precious metals, achieving cost reduction while maintaining catalytic performance.
4Quantity of substance
If oxide supports with defects are used, then cost is reduced, but catalyst stability and performance deteriorate
Solution Approach 1:
The patent applies local quality by allowing defects to exist in the support bulk while maintaining high quality at the cluster-support interface. The subnanometer clusters are positioned at specific locations on the support where they can tolerate or even benefit from local defects, achieving cost reduction without sacrificing stability.
Solution Approach 2:
The patent converts the harmful effect of support defects into a benefit by using subnanometer clusters that are small enough to be positioned at or near defect sites. These defects can enhance cluster dispersion, prevent aggregation, or create unique active sites, thereby improving both stability and activity while using cheaper defective supports.
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 achieves significantly higher turnover rates and reduced overpotentials, leading to more economical and efficient water splitting systems with extended electrode lifespan, capable of operating in harsh conditions.
Implementation Method 1
Oxygen evolution reactions (see Equations 1 and 2 infra) require high over potentials (η=0.3 ̃0.5 V depending on the catalytic material and support chosen).
Implementation Method 2
Water oxidation (i.e., water splitting) is a key catalytic step for electrical fuels generation. It consists of two reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER).
Data Source
AI summary
The invention provides a catalytic electrode for converting molecules, the electrode comprising a predetermined number of single catalytic sites supported on a substrate. Also provided is a method for oxidizing water comprising contacting the water with size selected catalyst clusters. The invention also provides a method for reducing an oxidized moiety, the method comprising contacting the moiety with size selected catalyst clusters at a predetermined voltage potential.