Single Sensor Alkane Oxygen Quantification via Ionic Liquid Electrolyte
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Solution Overview
Problem
The direct electrochemical oxidation of methane at room temperature is challenging due to slow electrode kinetics, and existing systems struggle to replicate the efficiency of nature's enzymatic oxidation using electrochemistry.
Innovation Solution
The use of ionic liquid electrolytes, such as alkyl substituted methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, facilitates electrochemical promotion of alkane oxidation and oxygen reduction/oxidation at a platinum or palladium electrode, enabling simultaneous quantification of alkane and oxygen using a single sensor with an electrochemically coupled reaction that regenerates oxygen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If direct electrochemical oxidation of methane is performed at room temperature, then energy efficiency is improved, but electrode kinetics become extremely slow
Solution Approach 1:
The patent introduces an intermediary substance (methane monooxygenase enzyme or synthetic catalyst) that mediates between methane and the electrode. This intermediary facilitates the oxidation reaction at room temperature by providing an alternative reaction pathway with lower activation energy, thereby resolving the contradiction between energy efficiency and electrode kinetics.
Solution Approach 2:
The patent changes the chemical environment parameters by using acid electrolytes or polyelectrolytes instead of conventional electrolytes. This parameter change creates a more favorable chemical environment for methane oxidation at room temperature, enabling the reaction to proceed at acceptable rates while maintaining energy efficiency.
2Productivity
If electrochemical systems are designed to replicate enzymatic oxidation, then reaction efficiency is improved, but device complexity increases
Solution Approach 1:
The patent extracts the catalytic function from the complex enzymatic system and isolates the essential activity into a simplified electrochemical system. By removing unnecessary biological components and focusing only on the catalytic oxidation function, the system achieves high reaction efficiency with reduced complexity.
Solution Approach 2:
The patent designs an electrochemical system that can perform multiple functions: methane oxidation, oxygen reduction, and energy generation. This multi-functionality allows a single device to replicate the essential capabilities of enzymatic oxidation without requiring separate systems for each function, thereby reducing overall device complexity.
3Device complexity
If a single sensor is used to quantify both alkane and oxygen, then device complexity is reduced, but measurement precision becomes challenging
Solution Approach 1:
The patent segments the measurement process into distinct temporal or spatial phases within a single sensor. The sensor alternates between measuring alkane oxidation current and oxygen reduction current, or uses separate electrode regions within the same sensor body. This segmentation allows precise quantification of both species while maintaining a single sensor device.
Solution Approach 2:
The patent employs feedback mechanisms where the measurement of one species (e.g., alkane oxidation) provides information that compensates for or corrects the measurement of the other species (oxygen reduction). This feedback loop enables accurate simultaneous quantification by accounting for cross-sensitivities and interference effects within the single sensor system.
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
This approach allows for efficient alkane oxidation and oxygen reduction at room temperature, enabling accurate detection and quantification of both species using a single sensor, with the method being suitable for various applications including energy storage and methane-based fuel cells.
Implementation Method 1
The direct oxidation of methane at low temperatures (e.g., from about 60° C. to about 150° C.) has been demonstrated with electrode systems utilizing acid electrolytes or polyelectrolytes
Implementation Method 2
The electrochemical oxidation of methane is thermodynamically favored
Implementation Method 3
oxygen reduction/oxidation at a platinum or palladium electrode
Implementation Method 4
an electrochemically coupled reaction that regenerates oxygen
Implementation Method 5
electrochemical promotion of alkane oxidation and oxygen reduction/oxidation at a platinum or palladium electrode
Data Source
AI summary
An alkane gas is supplied to an interface between an activated surface of a platinum or palladium working electrode and an ionic liquid electrolyte. The alkane adsorbs at or near an interface complex formed at the interface. The ionic liquid electrolyte is selected from a group consisting of 1-ethyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-propyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-pentyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-hexyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-heptyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-octyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-nonyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, and 1-decyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, and combinations thereof. While the alkane gas in the presence of oxygen is supplied to the interface, positive electrode potential is applied to the platinum or palladium working electrode, which causes oxidation of the adsorbed alkane to form a reaction product. A concentration of the alkane is quantified using an alkane anodic current or current density at the positive electrode potential. The alkane is used as an internal standard to calibrate oxygen detection.