Graphene-based PPB level sulfur detector
Inventors
Lock, Evgeniya H. • Perkins, F. Keith • Boyd, Anthony K. • Myers-Ward, Rachael L. • Gaskill, David Kurt • Nath, Anindya
Assignees
Publication Number
US-11789004-B2
Publication Date
2023-10-17
Expiration Date
2038-06-20
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Abstract
A sensitive and selective, in-line method to measure and validate the sulfur content at ppb levels in both the liquid and gas phase of an analyte. The method includes patterning graphene, for example to form a mesa structure comprising horizontal or vertical lines or an array of multidentate star features; functionalizing the patterned graphene and attaching nanoparticles to the functionalized graphene to form a device; exposing the device to an analyte in the gas or liquid phase; detecting a change in electrical response when sulfur is present in the analyte; and recovering the device for future use. Also disclosed is the related sulfur detector.
Core Innovation
The invention provides a sensitive and selective method for in-line detection of sulfur content at parts-per-billion (ppb) levels in both liquid and gas phases of fuel analytes. This method includes patterning graphene into specific structures, functionalizing the patterned graphene, and attaching metal oxide nanoparticles through a chemical linking molecule using UV-activated functionalization. The device formed detects sulfur presence by monitoring changes in electrical response upon exposure to the analyte, and it can be recovered for future use.
The problem addressed relates to the critical need for detecting trace sulfur concentrations in fuels, particularly for fuel cell applications. Sulfur rapidly degrades fuel cell catalysts even at very low concentrations, but existing methods for identifying sulfur breakthrough from desulfurizers are costly, unreliable, or operate blindly. Pristine graphene's high sensitivity lacks selectivity, especially under real-world interfering conditions. Functionalizing graphene with metal oxide nanoparticles enhances selectivity and sensitivity, enabling detection in the low ppb range for sulfur-containing compounds in fuels.
The invention achieves this by combining the exceptional surface-sensitive electrical properties of graphene with chemical functionalization by metal oxide nanoparticles such as ZnO, CuO, indium tin oxide (ITO), and Fe2O3. Patterned graphene structures, such as mesa configurations with strips or multidentate star features, are fabricated to engineer defects that improve the sensing response. Devices operate at room and elevated temperatures with fast response and recovery times, and their selective response enables differentiation among various sulfur compounds including thiophene, benzothiophene, and octanethiol.
Claims Coverage
The patent contains three independent claims that cover the method for sulfur detection, a sulfur detector device, and a sulfur detector system for ppb-level in-line detection.
Method for sulfur detection using patterned, functionalized graphene with nanoparticle attachment
A method involving patterning graphene, functionalizing it via UV-activated chemical functionalization, attaching metal oxide nanoparticles through a chemical linking molecule to form chemiresistive devices, then exposing these devices to gas or liquid analytes to detect sulfur by monitoring changes in electrical response and enabling recovery of the sensor for reuse.
Sulfur detector comprising patterned and functionalized graphene with nanoparticles
A sulfur detector made by the method of patterning graphene, functionalizing the patterned graphene, and attaching metal oxide nanoparticles via a chemical linking molecule to create chemiresistive devices, wherein the detector can be recovered after each use.
PPB level in-line sulfur detector system with functionalized etched graphene and metal oxide nanoparticles
A detector comprising functionalized etched graphene with attached metal oxide nanoparticles formed through UV-activated chemical functionalization and chemical linking molecules, combined with a measurement system to detect electrical response changes upon exposure to sulfur-containing fuels in gas or liquid phase.
The independent claims protect the method of preparing and using patterned, functionalized graphene with metal oxide nanoparticle attachments for sensitive electrical detection of sulfur in fuels, the resulting sulfur detector devices, and an in-line detection system capable of operating at ppb sulfur levels with recovery features.
Stated Advantages
Fast sensor response time—approximately 30 seconds for gas phase and 3 minutes for liquid phase sensing.
High selectivity towards key sulfur compounds such as thiophene, octanethiol, and benzothiophene in synthetic fuel mixtures.
Capability to detect sulfur content in both gas and liquid fuel phases, including aviation fuels with 20 ppm and 600 ppm sulfur.
Improved kinetics and response speed at elevated temperatures, with response times down to 10 seconds.
Device recovery via external heating or isopropanol rinsing enabling sensor reuse.
Extremely high sensitivity down to single-digit ppb levels (approximately 4 ppb for benzothiophene and 6 ppb for octanethiol) with predicted detection limits in the low ppt regime (<4 ppb).
Combination of pure and hybrid graphene/metal oxide devices allows development of a new class of sulfur sensing technology for in-line fuel analysis before combustion.
Documented Applications
Fuel cell power generation assets requiring sulfur-free fuel to prevent catalyst poisoning.
Portable fuel sensors to quickly identify suitable ('good') versus unsuitable ('bad') fuels for sulfur-sensitive applications.
Portable tools for the oil and gas industry to monitor sulfur content.
Fuel cell laboratory test equipment for fuel quality control.
Automotive fuel cell vehicles requiring monitoring of fuel sulfur concentration.
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