Atomically Dispersed Platinum Group Metal Catalysts for CO Oxidation
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Solution Overview
Problem
Conventional platinum group metal (PGM) catalysts used in heterogeneous catalysis have low atom efficiency, especially at high reaction temperatures, leading to increased costs due to the need for higher PGM loading and reduced dispersion, which affects their performance in catalytic reactions.
Innovation Solution
Development of highly active, atomically dispersed PGM nanocatalysts, such as Pt, Pd, Rh, and Ir, supported on reducible metal oxides like Fe2O3 and CeO2, which achieve near 100% atom efficiency by dispersing single PGM atoms or clusters, significantly enhancing catalytic activity for CO oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional nanoparticle PGM catalysts are used, then catalytic activity is maintained, but atom efficiency is low and PGM loading must be high
Solution Approach 1:
The patent segments PGM material from traditional nanoparticle form into individual atomically dispersed species on the catalyst surface. This segmentation achieves near 100% atom efficiency by ensuring every PGM atom is exposed and catalytically active, eliminating the inactive core regions present in nanoparticles. The atomic dispersion is achieved through controlled synthesis methods that prevent particle aggregation while maintaining metal atom integrity.
Solution Approach 2:
The patent changes the structural parameter of PGM from nanoscale particles (typically 2-10 nm) to atomic-scale dispersed species (0.1-0.5 nm). This parameter change fundamentally alters the catalytic properties by maximizing the surface-to-volume ratio to its theoretical limit, where essentially all metal atoms are surface atoms available for catalysis. The atomic dispersion state is stabilized through interaction with specific support materials and controlled reduction conditions.
2Reliability
If PGM particle size is increased, then catalyst stability is improved, but dispersion decreases and atom efficiency drops
Solution Approach 1:
The patent introduces a support material as an intermediary between PGM atoms and the reaction environment. The support (typically metal oxides like Al2O3, SiO2, TiO2, or CeO2) provides anchoring sites that stabilize individual PGM atoms or small clusters, preventing their aggregation into larger particles. The support acts as a spatial organizer that maintains atomic dispersion while providing thermal and mechanical stability to the catalyst structure during operation.
Solution Approach 2:
The patent creates composite catalyst structures combining PGM atoms with metal oxide supports in a defined architecture. These composite materials leverage the synergistic effects between the metal atoms and oxide support, where the support provides structural stability and the metal atoms provide catalytic activity. The composite structure enables simultaneous achievement of high dispersion and operational stability that cannot be achieved with pure metal particles alone.
3Productivity
If high PGM loading is used, then desired catalytic performance is achieved, but catalyst cost increases
Solution Approach 1:
The patent enables the catalyst structure to self-optimize PGM utilization through atomic dispersion. Each PGM atom serves itself as a complete catalytic center with all necessary coordination sites exposed, eliminating the need for excess PGM to compensate for inefficient utilization in nanoparticle form. The atomic dispersion state ensures that every atom contributes to catalytic activity, achieving near 100% atom efficiency and dramatically reducing the total PGM quantity needed for a given performance level.
4Quantity of substance
If atomically dispersed PGM catalysts are used, then atom efficiency approaches 100%, but catalytic activity per gram must be extremely high to compensate for low loading
Solution Approach 1:
The patent enhances the local quality of each PGM atom by optimizing its coordination environment and electronic structure through precise control of synthesis conditions and support selection. Atomic dispersion exposes all coordination sites of each metal atom, creating maximally active local centers. The local electronic properties are tuned through interaction with the support material, creating highly active sites with optimized binding energies for reactants and intermediates, thereby achieving extremely high turnover frequencies at atomic dispersion sites.
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 resulting catalysts exhibit turnover frequencies exceeding 1,500 s−1 for CO oxidation at 350° C, more than 100 times higher than conventional nanoparticle counterparts, reducing CO emissions effectively and potentially lowering catalyst costs.
Implementation Method 1
Group 10 (platinum group metal or PGM) nanocatalysts (Pt, Pd, Rh, Ir, Ru) including isolated single PGM atoms or clusters of PGM atoms on reducible metal oxide supports, for which the atom efficiency of the PGMs approaches 100%. When these PGM atoms or clusters act as highly active catalytic centers
Implementation Method 2
These catalysts can possess high activities for oxidation of carbon monoxide (CO) to carbon dioxide (CO2) in a wide temperature range
Implementation Method 3
supported on reducible metal oxides like Fe2O3 and CeO2
Data Source
AI summary
A nanocatalyst including single atoms of platinum dispersed on a nanoscale metal oxide, and the nanocatalyst comprises 0.01 wt % to 1 wt % platinum. Preparing the nanocatalyst includes combining a solution comprising a nanoscale metal oxide and a compound containing a Group 10 metal to yield a mixture, aging the mixture for a length of time, filtering the mixture to yield a solid, washing the solid to eliminate water soluble anions, and calcining the solid to yield a nanocatalyst including single atoms or clusters of atoms of the Group 10 metal on the nanoscale metal oxide.