Single-Atom Catalyst Hierarchical Structure for Methane Conversion
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Solution Overview
Problem
Current methods for converting methane to higher value chemicals like ethylene are inefficient, relying on indirect and complex Fischer-Tropsch technology, resulting in high capital costs and significant greenhouse gas emissions, while direct conversion methods face challenges in selectivity and thermal stability of single-atom catalysts.
Innovation Solution
A single-atom-based catalyst system with controlled hierarchical structures is developed, comprising core-shell nanoparticles and superlattices, optimized through lattice-strain engineering and 3D printing, to enhance the selectivity and activity of single-atom catalytic sites for the direct conversion of methane to ethylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If indirect Fischer-Tropsch technology is used for methane conversion, then the process is well-established and reliable, but capital costs are high and the process complexity increases
Solution Approach 1:
The catalyst system is segmented into distinct hierarchical levels: single-atom catalytic sites anchored on nanoparticle surfaces, nanoparticles organized into superparticle assemblies, and superparticles arranged in structured catalyst beds. This segmentation allows each level to be optimized independently for specific functions (activation, conversion, selectivity) while simplifying the overall process design compared to complex Fischer-Tropsch synthesis
Solution Approach 2:
Single-atom catalysts provide localized active sites with uniform composition and structure, ensuring consistent catalytic performance. The hierarchical structure creates localized regions with different porosity and density characteristics optimized for specific reaction stages, improving overall process efficiency without increasing complexity
2Productivity
If single-atom catalysts are used for direct methane conversion, then selectivity and activity are improved, but thermal stability deteriorates
Solution Approach 1:
Single-atom catalysts are nested within nanoparticle structures, which are in turn nested within superparticle assemblies. This nested hierarchical structure protects the thermally sensitive single-atom sites while maintaining their catalytic activity, as the larger structural units provide thermal stability and structural integrity during high-temperature methane conversion
Solution Approach 2:
The system combines single-atom catalysts with support materials to form composite nanoparticle structures. These composites integrate the high activity of single-atom sites with the thermal stability of the supporting nanoparticle framework, resolving the contradiction between activity and thermal stability
3Ease of manufacture
If conventional catalyst structures are used, then manufacturing is simpler, but selectivity and conversion efficiency are lower
Solution Approach 1:
The single-atom catalysts are pre-anchored onto nanoparticle surfaces during synthesis, creating stable and well-defined catalytic sites before the actual methane conversion process. This preliminary structuring ensures high selectivity and activity from the start, while the modular hierarchical design allows for scalable manufacturing using established nanoparticle synthesis techniques
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 enables efficient and selective conversion of methane to ethylene, reducing capital costs and greenhouse gas emissions, and allows for the use of abundant domestic natural gas, making the process economically viable and environmentally friendly.
Implementation Method 1
one or more single-atom catalysts anchored to the support surface, wherein the density and location of the single-atom catalysts on the support surface are controlled within a 20% variance to provide a highly uniform spatial distribution of single-atom catalysts
Data Source
AI summary
The disclosure relates to a single-atom-based catalyst system with total-length control of single-atom catalytic sites. The single-atom-based catalyst system comprises at least one catalyst structure comprising a first assembly of a plurality of single-atom-catalyst superparticles. The single-atom-catalyst superparticles comprise a second assembly of a plurality of single-atom-catalyst nanoparticles. The single-atom-based catalyst system has controlled porosity and spatial distribution of active single-atom catalysts from the atomic scale to the macroscopic scale. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.