Plasma modified epitaxial fabricated graphene on SiC for electrochemical trace detection of explosives
Inventors
Trammell, Scott A. • Myers-Ward, Rachael L. • Hangarter, Sandra C. • Zabetakis, Daniel • Stenger, David A. • Gaskill, David Kurt • Walton, Scott G.
Assignees
Publication Number
US-10928351-B2
Publication Date
2021-02-23
Expiration Date
2038-07-30
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Abstract
An electrochemical cell includes a working electrode in contact with an aqueous electrolyte solution, a counter electrode in contact with the aqueous electrolyte solution, and a reference electrode in contact with the aqueous electrolyte solution. The working electrode comprises a plasma modified epitaxial synthesized graphene surface fabricated on SiC.
Core Innovation
The invention describes an electrochemical cell with a working electrode made of plasma modified epitaxial synthesized graphene on SiC, used for improved electrochemical detection of TNT. The working electrode comprises a graphene surface fabricated on SiC and chemically modified via electron beam-generated plasmas introducing oxygen or nitrogen functionalities, enhancing the detection signal without requiring traditional accumulation or amplification steps.
The invention addresses limitations in existing graphene-based electrochemical sensors for nitroaromatics like TNT, including the need for electrochemical accumulation steps, large sample volumes for preconcentration, or signal amplification techniques such as redox cycling. Additionally, prior preparation methods for working electrodes posed challenges for scalable, industrial mass production.
The method for manufacturing includes preparing SiC surfaces by H2 etching, epitaxial graphene growth by sublimating Si from SiC substrates in a chemical vapor deposition reactor under controlled temperature and pressure, followed by cooling and plasma chemical modification using pulsed electron beams in reactive gas mixtures to control oxygen or nitrogen functional group density on the graphene surface. This synthesis and modification process enables high-throughput, large-area, industrially scalable production of electrochemical sensors with improved TNT detection sensitivity.
Claims Coverage
The patent contains one independent claim detailing an electrochemical cell featuring a plasma modified epitaxial graphene working electrode on SiC.
Working electrode featuring plasma modified epitaxial graphene synthesized from SiC
An electrochemical cell comprising a working electrode in contact with an aqueous electrolyte solution, wherein the working electrode comprises a plasma modified epitaxial graphene surface synthesized from SiC, along with counter and reference electrodes also in contact with the electrolyte.
The claim encompasses the electrochemical cell design wherein the key inventive feature is the use of a plasma modified epitaxial graphene working electrode fabricated on SiC for electrochemical detection purposes.
Stated Advantages
Improved electrochemical detection sensitivity for TNT with a limit of detection around 20 ppb without the need for accumulation, preconcentration, or amplification steps.
High-throughput, high-volume synthesis process amenable to industrial scale production.
Large area epitaxial graphene growth on SiC substrates combined with rapid, low-waste plasma processing enables low-cost mass production of sensors.
Electrical properties of graphene are enhanced through plasma chemical modification introducing controlled oxygen or nitrogen surface functionalities, improving electron transfer kinetics and signal amplitude.
Documented Applications
Electrochemical detection and identification of explosives such as TNT, including their precursors and degradation products in environmental samples.
Miniaturized, low-power electrochemical sensors for trace detection of nitro-aromatic explosives.
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