Platinum Cobalt Catalyst for Low-Temperature CO Oxidation
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Solution Overview
Problem
Current catalysts for the selective oxidation of carbon monoxide (CO) in hydrogen-rich gas streams, such as those used in fuel cells, suffer from low thermal stability, sensitivity to moisture and CO2, and incomplete CO removal, especially at low temperatures, which hampers their effectiveness in preventing electrode poisoning and air purification applications.
Innovation Solution
A platinum and cobalt-based catalyst system is developed, where the support structure is co-impregnated with platinum and cobalt precursors in an acidic medium, specifically using tetrammineplatinum(II) nitrate and cobalt(IV) nitrate, and citric or tartaric acid, on high-surface-area silicon dioxide or zirconium phosphate supports, optimizing the Pt/Co ratio and impregnation process for enhanced activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold or silver catalysts are used for selective oxidation of CO, then catalytic activity is achieved, but thermal stability and stability under reaction conditions deteriorate due to partial deactivation
Solution Approach 1:
The patent uses a composite catalyst system combining platinum and cobalt on a titanium dioxide support. This composite structure leverages the high catalytic activity of platinum for CO oxidation while cobalt enhances thermal stability and resistance to deactivation. The synergistic interaction between Pt and Co components resolves the contradiction by maintaining both high productivity and reliability under reaction conditions.
Solution Approach 2:
The patent optimizes specific parameters including the Pt/Co ratio, metal loading amounts, and calcination temperature to achieve the desired balance between activity and stability. By carefully controlling these parameters during catalyst preparation, the system achieves complete CO conversion while maintaining long-term stability under fuel cell operating conditions.
2Quantity of substance
If copper-based catalysts are used for CO oxidation, then cost is reduced, but activity below 200°C deteriorates and sensitivity to water and CO2 increases
Solution Approach 1:
The patent employs platinum and cobalt precursors with specific chemical properties that enable effective co-impregnation and formation of stable active phases. The choice of precursors and optimization of impregnation parameters allow achieving high low-temperature activity while maintaining cost-effectiveness through efficient metal utilization.
3Reliability
If the oxidation of CO is performed with small amounts of oxygen, then selectivity for CO oxidation is improved, but complete CO removal at low temperatures deteriorates
Solution Approach 1:
The Pt-Co composite catalyst on TiO2 support creates multiple active sites with different functions. Platinum provides high selectivity for CO oxidation while cobalt promotes oxygen activation and surface oxygen species formation. This composite structure enables complete CO conversion at low temperatures by providing both selective CO oxidation pathways and enhanced oxygen availability.
Solution Approach 2:
The titanium dioxide support provides a porous structure with high surface area that facilitates oxygen diffusion and adsorption. The porous structure allows small amounts of oxygen to be effectively distributed throughout the catalyst bed, enabling complete CO removal at low temperatures while maintaining high selectivity through the confined reaction pathways.
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 complete CO conversion at low temperatures with a wide temperature window and high space velocities, effectively preventing electrode poisoning and CO removal in fuel cells, diesel engines, and air purification systems, while maintaining stability and resistance to sulfur poisoning.
Implementation Method 1
a support structure is co-impregnated in an acidic medium. The acidic medium comprises at least one platinum precursor and at least one cobalt precursor
Implementation Method 2
The co-impregnation is then followed by drying and calcination of the support structure
Implementation Method 3
The co-impregnation is then followed by drying and calcination of the support structure
Implementation Method 4
the oxidation of CO by addition of small amounts of oxygen... the selective oxidation of CO (SelOx)... a catalyst for the oxidation of carbon monoxide (CO) at low temperatures
Implementation Method 5
a catalytically active composition based on platinum and cobalt... a catalyst for the oxidation of carbon monoxide (CO) at low temperatures
Data Source
AI summary
The invention relates to a catalyst for the oxidation of carbon monoxide (CO) at low temperatures, which is a catalytically active composition based on platinum and cobalt. The catalyst can be used in the removal of CO from hydrogen-rich gas for fuel cell technology in order to avoid poisoning the electrodes with CO. Further fields of application relate to the automobile sector, and in particular, to the effective removal of CO during cold starting of a diesel or petrol engine and also to air purification systems for quality control of air in interior spaces, e.g., the removal of CO in a tunnel, an underground railway, multi-story car parks or submarines.