Iron-Based Catalyst for Direct CO2 Hydrogenation
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Solution Overview
Problem
There is no commercial process for directly converting carbon dioxide to alkanes/olefins, as existing methods require conversion of CO2 to carbon monoxide and subsequent reaction with hydrogen.
Innovation Solution
An iron-based catalyst comprising 70 mol% to 97 mol% of porous FeO(OH)x, where 1<x<2, and 3 mol% to 30 mol% of an alkaline metal compound is used to directly convert carbon dioxide and hydrogen into alkanes/olefins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional hydrogenation process using CO/H2 syngas is used, then alkanes/olefins can be produced, but carbon dioxide cannot be directly converted and additional conversion steps are required
Solution Approach 1:
The invention changes the chemical composition parameters of the catalyst by incorporating iron oxide-hydroxide (FeO(OH)x) with specific oxidation states and alkaline metal compounds, enabling direct CO2 activation and conversion without requiring intermediate CO formation steps, thus simplifying the overall process while maintaining versatility
Solution Approach 2:
The iron oxide-hydroxide catalyst acts as an intermediary that facilitates the direct conversion of CO2 to alkanes/olefins by providing active sites for CO2 activation and reaction with hydrogen, eliminating the need for separate CO formation and conversion steps
2Productivity
If carbon dioxide is converted via carbon monoxide intermediate, then alkanes/olefins can be formed, but conversion efficiency is reduced
Solution Approach 1:
The invention segments the catalytic function into distinct active sites within the iron oxide-hydroxide structure, where one site activates CO2 and another facilitates hydrogenation, enabling the entire conversion process to occur in a single step rather than requiring sequential CO formation and conversion steps
Solution Approach 2:
The invention merges the CO2 activation function and hydrogenation function into a single catalyst system (iron oxide-hydroxide with alkaline metal compounds), allowing both steps to occur simultaneously and directly convert CO2 to alkanes/olefins without intermediate CO formation
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 catalyst achieves a conversion rate of carbon dioxide to alkanes/olefins ranging from 50% to 80%, with yields of C1-3 alkanes/olefins between 45% to 75%, significantly improving upon conventional methods.
Implementation Method 1
contacting carbon dioxide and hydrogen with an iron-based catalyst to form a liquid and a gas
Implementation Method 2
an iron-based catalyst comprising 70 mol% to 97 mol% of porous FeO(OH)x, where 1<x<2, and 3 mol% to 30 mol% of an alkaline metal compound is used to directly convert carbon dioxide and hydrogen into alkanes/olefins
Data Source
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AI summary
A method of hydrogenating carbon dioxide, including contacting carbon dioxide and hydrogen with an iron-based catalyst to form a liquid and a gas. The liquid includes CnH2n, CnH2n+2, or a combination thereof and water, wherein n is 5 to 18. The gas includes CH4, CmH2m, CmH2m+2, or a combination thereof, hydrogen, and carbon dioxide, wherein m is 2 to 9. The iron-based catalyst includes 70 mol% to 97 mol% of porous FeO(OH)x (wherein 1<x<2), and 3 mol% to 30 mol% of alkaline metal compound loaded onto the porous FeO(OH)x.