Carbon-Embedded Iron Nanoparticles for High-Loading Catalysts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for synthesizing transition metal nanoparticles with catalytic activity face limitations due to low active metal concentrations and clustering, resulting in materials with low dispersion and uniform coordination, which hinders high catalytic activity.
Innovation Solution
A catalytically active material comprising grains of non-graphitizing carbon with iron nanoparticles dispersed within, where the average diameter of iron nanoparticles ranges from 1 nm to 20 nm, and the average distance between them is between 2 nm to 150 nm, with a combined metal mass fraction of 30 wt% to 70 wt%, achieved through a process involving an aqueous solution of iron precursors and organic carbon sources, followed by spray drying or freeze drying and thermo-treating at moderate temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional impregnation or chemical vapor deposition methods are used to synthesize transition metal nanoparticles on supports, then the material can be obtained with moderate metal content, but the metal particles exhibit clustering and low dispersion, resulting in low active metal concentration (less than 20 wt %) and poor catalytic activity
Solution Approach 1:
The patent applies preliminary action by pre-forming molecular complexes of transition metals with organic ligands in solution before deposition onto the support. This pre-organization of metal species at the molecular level ensures uniform distribution and prevents clustering during subsequent thermal treatment, enabling high metal content (30-70 wt %) while maintaining excellent dispersion and coordination uniformity
Solution Approach 2:
The patent utilizes parameter changes by controlling the thermal treatment temperature and atmosphere to transform the pre-formed molecular complexes into nanoparticles in-situ. By optimizing the heating profile and chemical environment during thermal treatment, the method achieves controlled nanoparticle formation with desired size distribution and high metal content without aggregation, resolving the contradiction between quantity and dispersion
2Quantity of substance
If high metal content is attempted in conventional supported nanoparticle materials, then the active metal concentration increases, but the metal particles cluster and lose dispersion, reducing catalytic performance
Solution Approach 1:
The patent employs preliminary action by forming stable molecular complexes of transition metals with organic ligands before deposition. These pre-formed complexes act as templates that maintain uniform metal distribution even at high concentrations (30-70 wt %). During thermal treatment, the complexes decompose in-situ to form nanoparticles that inherit the uniform spatial distribution and coordination geometry from the parent molecular structures, preventing clustering and maintaining compositional stability
Solution Approach 2:
The patent uses organic ligands as intermediaries that temporarily stabilize transition metal species in a uniform, dispersed state during the synthesis process. These ligands act as spacers and protective shells that prevent metal-metal aggregation. During controlled thermal treatment, the ligands decompose in a controlled manner, leaving behind uniformly dispersed metal nanoparticles with high content (30-70 wt %) and maintained coordination uniformity
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 material exhibits high catalytic activity in various chemical reactions, with a high content of iron nanoparticles conforming to specific size and distance relations, enhancing reaction rates without being consumed by the catalyzed reaction.
Implementation Method 1
spray drying or freeze drying the aqueous solution of metal precursor and organic carbon source
Implementation Method 2
spray drying or freeze drying the aqueous solution of metal precursor and organic carbon source
Implementation Method 3
thermo-treating intermediate product P at a temperature in the range from 200° C. to 380° C.
Implementation Method 4
thermo-treating intermediate product P at a temperature in the range from 200° C. to 380° C.
Data Source
AI summary
The present invention relates to catalytically active material, comprising grains of non-graphitizing carbon with iron nanoparticles dispersed therein, wherein dp, the average diameter of iron nanoparticles in the non-graphitizing carbon grains, is in the range of 1 nm to 20 nm, D, the average distance between iron nanoparticles in the non-graphitizing carbon grains, is in the range of 2 nm to 150 nm, and ω, the combined total mass fraction of metal in the non-graphitizing carbon grains, is in the range of 30 wt % to 70 wt % of the total mass of the non-graphitizing carbon grains, and wherein dp, D and ω conform to the following relation: 4.5 dp/ω>D≥0.25 dp/ω. The present invention, further, relates to a process for the manufacture of material according to the invention, as well as its use as a catalyst.