United States. The research team from NETL and the University of Pittsburgh demonstrates the use of plasmonic nanomaterials (pNP) and porous polymer composite coatings in fiber-optic sensing technologies that can detect energy-relevant gases.
These gases include carbon dioxide (CO2) and methane (CH4).
The technology can help ensure safer and faster underground storage and pipeline monitoring.
Fiber optic sensors offer advantages over other types of sensors because they are small, lightweight, can withstand high temperatures and pressures, and are immune to electromagnetic interference. In addition, fiber optic sensors feature long-range, spatially distributed monitoring.
The latest research demonstrates how pNP plasmonic nanoparticles can be incorporated into porous polymer coating to enhance the monitoring capabilities of fiber optic sensors to leverage extensive research in distributed sensor technology at NETL.
pNPs, including gold, silver and platinum particles, are discrete metal particles or metal oxide particles, such as tin-doped indium oxide (ITO), which have unique optical properties due to their size and shape and are increasingly incorporated into commercial products and technologies.
pNPs have unique optical, electrical and thermal properties that make them effective for use in applications such as antimicrobial coatings and molecular diagnostics.
pNP-based sensing technologies are of interest for various chemical, biological, environmental and medical applications. Plasmonic gas sensors exhibit high sensitivity, but until recently they had not been shown to work with chemically stable gases such as CO2 at room temperature.
In this specific case, NETL researchers Ki-Joong Kim, Jeffrey T. Culp, Jeffrey Wuenschell, Ali K. Sekizkardes, and former NETL researchers Roman A. Shugayev and Paul R. Ohodnicki developed the highly sensitive material that can be used to detect CO2 (or CH4) in ambient environments.
The researchers created a composite film that provides distinct and tunable optical characteristics on a fiber-optic platform that can be used as a signal transducer for gas detection in atmospheric conditions.
The researchers explain that by varying the pNP content in a polymer matrix, the optical behavior of the composite film can be adjusted to affect the operating wavelength by more than several hundred nanometers and the sensitivity of the sensor in the near-infrared range.
Tuning plasmon resonance in the near-infrared range is particularly important in distributed or quasi-distributed sensing approaches, which are more compatible with distributed interrogation systems.
The research also demonstrated that pNPs polymer composite film exhibits remarkable long-term stability by mitigating the problem of physical polymer aging. The sensor can operate in atmospheric conditions without significant signs of degradation.
"Advances in sensing technologies are important for a clean energy future, including safe underground storage of CO2 and detection of CH4 leaks," said Ruishu Wright, NETL functional materials team.
"Visibility and tracking are important for assessing and managing the operational risks of underground CO2 storage. Real-time monitoring is needed to ensure the integrity of storage infrastructure and pipelines and to detect early signs of gas leaks," Wright continued.
There are many commercial gas sensors for CO2 or CH4 in operation, including catalytic combustion sensors, electrochemical sensors, thermoconductivity sensors, resistive sensors, acoustic leak sensors, and optical sensors. But the challenge is that existing sensor technologies are mostly point or separation sensors.
"There is a real need for wide-area and long-distance monitoring for CO2 and CH4 leak detection in large-scale storage facilities and for CH4 gas detection in wells and industrial facilities. Early detection of greenhouse gas leaks will help mitigate greenhouse gas emissions and combat global warming," Wright added.