Platinum-Iron Catalyst for Selective CO Oxidation in Hydrogen Streams
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Solution Overview
Problem
Current methods for purifying hydrogen-rich streams for fuel cells are hindered by the presence of carbon monoxide, which poisons platinum-based catalytic compositions in PEM fuel cells, as the carbon monoxide content remains significant even after processing in shift reactors.
Innovation Solution
A catalytic composition is prepared by incorporating a hydrocarbon into an alumina-containing compound, spraying a platinum-iron mixture onto it, sulfiding, calcining, steaming, and reducing the support to create a catalyst that effectively oxidizes carbon monoxide to carbon dioxide in the presence of hydrogen and oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional steam reforming and shift reactor processing are used to purify hydrogen-rich streams, then hydrogen production is achieved, but carbon monoxide content remains at 0.2-2% which is sufficient to poison platinum-based catalysts in PEM fuel cells
Solution Approach 1:
The invention changes the chemical state of the catalyst surface by introducing sulfur compounds during preparation, creating a sulfided catalyst surface that is selective for CO oxidation. This parameter change in catalyst surface chemistry enables the catalyst to selectively oxidize CO to CO2 at temperatures below 100°C, reducing CO content from 0.2-2% to below 10 ppm, thereby eliminating catalyst poisoning while preserving hydrogen for fuel cell use
Solution Approach 2:
The invention uses a composite catalyst system comprising platinum and iron on an alumina support with hydrocarbon treatment. This composite material combines the high CO oxidation activity of platinum with the selective properties of iron-sulfur compounds, creating a synergistic effect that enables selective CO oxidation in the presence of hydrogen without requiring extreme temperatures or complex multi-stage processing
2Object-affected harmful factors
If carbon monoxide is oxidized using conventional catalysts, then carbon monoxide is converted to carbon dioxide, but the process requires high temperatures and does not selectively oxidize CO in the presence of hydrogen
Solution Approach 1:
The invention fundamentally changes the operational temperature parameter by preparing the catalyst with sulfur compounds and hydrocarbons, which create surface sites that enable CO oxidation at temperatures below 100°C. This parameter change allows selective CO oxidation to proceed under mild conditions that preserve hydrogen and avoid thermal decomposition of other components
Solution Approach 2:
The invention introduces oxygen in controlled amounts to create a selective oxidation environment. The sulfided catalyst surface activates oxygen to form reactive oxygen species that preferentially oxidize CO to CO2 while leaving hydrogen unaffected, enabling efficient CO removal at low temperatures through accelerated selective oxidation
3Ease of manufacture
If a catalytic composition is prepared using conventional methods, then the catalyst can be manufactured, but it lacks the selectivity and activity for low-temperature CO oxidation in hydrogen-rich streams
Solution Approach 1:
The invention performs preliminary actions during catalyst preparation by incorporating sulfur compounds and hydrocarbons into the catalyst structure before use. The hydrocarbon is incorporated into the alumina pores, followed by sulfiding treatment that creates the active sulfided catalyst surface. These preliminary steps establish the selective properties needed for low-temperature CO oxidation, ensuring high reliability and activity when the catalyst is deployed in fuel cell applications
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 process significantly reduces carbon monoxide levels in hydrogen-rich streams, preventing catalyst poisoning and enhancing the efficiency of hydrogen fuel for fuel cells by achieving high CO conversion rates, as demonstrated in various examples.
Implementation Method 1
a catalytic composition is prepared by incorporating a hydrocarbon into an alumina-containing compound, spraying a platinum-iron mixture onto it, sulfiding, calcining, steaming, and reducing the support to create a catalyst that effectively oxidizes carbon monoxide to carbon dioxide in the presence of hydrogen and oxygen
Data Source
AI summary
A method of making a composition, said method comprising, spraying a substance comprising platinum and iron into or onto an alumina-containing compound is disclosed. The resulting composition can then be used in a process for oxidizing carbon monoxide with free oxygen.