Cubic Fluorite Rare-Earth High-Entropy Oxide Catalysts
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Solution Overview
Problem
Existing catalysts face challenges in efficiently converting CO2 into methane due to thermodynamic and kinetic limitations, with noble metals being costly and transition metals like Ni exhibiting lower activity and selectivity.
Innovation Solution
Development of Ceria-based mixed metal high entropy oxide (HEO) catalysts, specifically CeLaPrSmGdO, supported by Ni, synthesized through co-precipitation or dry ball milling methods, maintaining a single phase composition and facilitating the water gas shift reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If noble metals (Pd, Pt, Ir, Rh, Ru) are used as catalysts for CO2 methanation, then catalytic activity and selectivity are improved, but cost increases significantly
Solution Approach 1:
The patent changes the compositional parameters by incorporating multiple rare earth elements (La, Pr, Nd, Sm, Gd) in varying ratios to optimize catalytic performance. By adjusting the elemental composition and oxidation states, the catalyst achieves high activity comparable to noble metals while using abundant, low-cost transition metals as the base
Solution Approach 2:
The patent creates a composite catalyst system combining transition metals (Co, Fe, Ni, Cu, Zn) with rare earth oxides in a high-entropy configuration. This composite structure synergistically combines the CO2 activation capability of transition metals with the stability and selectivity enhancement from rare earth elements, achieving noble-metal-level performance at lower cost
2Quantity of substance
If transition metals (Co, Fe, Ni, Cu, Zn) are used as catalysts for CO2 methanation, then cost is reduced, but catalytic activity and selectivity decrease compared to noble metals
Solution Approach 1:
The patent merges five different metal cations (Co, Fe, Ni, Cu, Zn) with five rare earth elements (La, Pr, Nd, Sm, Gd) into a single high-entropy oxide phase. This merging creates a synergistic effect where the combination of metals with different electronic structures and catalytic properties produces enhanced overall activity and selectivity that exceeds individual metal performance
Solution Approach 2:
The patent creates local active sites with specific metal combinations and oxidation states within the high-entropy oxide structure. Different regions of the catalyst surface provide specialized functions: some sites optimize CO2 adsorption, others facilitate H2 activation, and others promote methane formation, thereby achieving high overall activity through distributed local quality optimization
3Stability of the object's composition
If multi-element HEO catalysts are synthesized through coprecipitation or dry ball milling, then single phase composition is maintained, but synthesis complexity increases
Solution Approach 1:
The patent performs preliminary mixing of all metal precursors before the actual synthesis reaction. In coprecipitation, all metal salts are dissolved and mixed in predetermined ratios before adding the precipitating agent. In dry ball milling, all metal powders are pre-mixed for extended periods. This preliminary homogeneous distribution prevents phase segregation and ensures single-phase HEO formation
Solution Approach 2:
The patent optimizes synthesis parameters including pH value, temperature, pressure, and reaction time to favor single-phase formation. By carefully controlling these parameters during coprecipitation or ball milling, the system maintains thermodynamic conditions that promote the formation of a single high-entropy oxide phase rather than multiple separate phases
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 HEO catalysts demonstrate enhanced CO2 conversion to methane with improved selectivity and stability, overcoming the limitations of traditional catalysts by maintaining a single phase structure from room temperature to 900°C, and achieving high CO2 conversion and methane yield.
Implementation Method 1
HEO catalysts facilitating the water gas shift reaction
Implementation Method 2
dissolving the precursor salts of dopants and coprecipitating the HEO as a slurry mixture
Implementation Method 3
coprecipitating the HEO as a slurry mixture
Implementation Method 4
The water is then evaporated
Data Source
AI summary
In general, the embodiments of the present disclosure describe Ceria-based mixed metal high entropy oxide (HEO) catalysts, namely CeLaPrSmGdO, its Nickel supported counterpart catalysts for use in water gas shift reaction and methods of making Ceria based mixed metal high entropy oxide catalysts and Nickel supported mixed metal high entropy oxide catalysts.