CeO2-Supported Single Atom Catalysts for Direct Methane Conversion
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Solution Overview
Problem
Conventional methods for methane conversion to olefins and aromatics face challenges such as low carbon efficiency, high capital costs, and carbon coking due to the presence of metal ensembles in catalysts, limiting their stability and selectivity.
Innovation Solution
The synthesis of single atom noble metal catalysts supported on CeO2, specifically Pt, Pd, Rh, Ru, Ag, Au, and Ir, which are characterized by atomic dispersion and absence of clusters, allowing for efficient non-oxidative methane conversion to light olefins and aromatics with reduced coke selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalysts with metal ensembles are used for methane conversion, then catalytic activity is achieved, but carbon coking occurs and stability is limited
Solution Approach 1:
The catalyst structure is segmented to the atomic level, with individual noble metal atoms dispersed on CeO2 support. This atomic-level segmentation eliminates metal ensembles and prevents carbon coking while maintaining catalytic activity for methane conversion to olefins and aromatics
Solution Approach 2:
The invention creates localized atomic dispersion of noble metal atoms on specific CeO2 support sites. This local quality control ensures that catalytic sites are isolated at the atomic level, preventing carbon deposition while maintaining high activity for C-C coupling reactions
2Manufacturing precision
If single atom catalysts are synthesized, then atomic dispersion and absence of clusters are achieved, but synthesis complexity increases
Solution Approach 1:
CeO2 nanoparticles serve as an intermediary support that facilitates the formation and stabilization of single atom noble metal catalysts. The CeO2 support provides specific sites for atomic dispersion and prevents cluster formation during synthesis and reaction, simplifying the overall synthesis process while achieving atomic-level precision
Solution Approach 2:
The invention employs controlled synthesis parameters including temperature, atmosphere, and precursor ratios to achieve atomic dispersion. By optimizing these parameters, the synthesis process achieves precise atomic-level control without requiring excessively complex procedures
3Productivity
If conventional multistage syngas processes are used, then methane conversion is achieved, but carbon efficiency is low and capital cost is high
Solution Approach 1:
The invention extracts and eliminates the intermediate syngas step from the conventional methane conversion process. By using single atom catalysts, the process directly converts methane to olefins and aromatics in one step, improving carbon efficiency and reducing energy losses associated with multiple conversion stages
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 CeO2-supported single atom catalysts demonstrate superior catalytic performance and stability, achieving high methane conversion and selectivity towards C2 productivity with minimal coke formation, making them suitable for practical applications.
Implementation Method 1
Single atom catalysts (SACs) represent a new frontier of heterogeneous catalysis and have been demonstrated to exhibit enhanced catalytic activity and selectivity in many reactions, including CO oxidation, water-gas shift, methane steam reforming, selective hydrogenation of alkynes and dienes and so on
Implementation Method 2
The superior catalytic performance can be attributed to the atomic dispersion of metal atoms with low coordination number, quantum confinement and/or strong metal-support (mostly metal oxides) interactions
Implementation Method 3
The superior catalytic performance can be attributed to the atomic dispersion of metal atoms with low coordination number, quantum confinement and/or strong metal-support (mostly metal oxides) interactions
Data Source
AI summary
Described are methods for converting methane to olefins, aromatics, or a combination thereof using a single atom catalyst comprising CeO2 nanoparticles impregnated with individual atoms of noble metals including Pt, Pd, Rh, Ru, Ag, Au, Ir, or a combination thereof. These single atom catalysts of the present invention are heated with methane to form olefins and aromatics.