Graphene Foam Detects Explosives, Emissions Better Than Today's Gas Sensors

A new study from Rensselaer Polytechnic Institute demonstrates how graphene foam can outperform leading commercial gas sensors in detecting potentially dangerous and explosive chemicals. The discovery opens the door for a new generation of gas sensors to be used by bomb squads, law enforcement officials, defense organizations, and in various industrial settings. The new sensor successfully and repeatedly measured ammonia (NH3) and nitrogen dioxide (NO2) at concentrations as small as 20 parts-per-million. Made from continuous graphene nanosheets that grow into a foam-like structure about the size of a postage stamp and thickness of felt, the sensor is flexible, rugged, and finally overcomes the shortcomings that have prevented nanostructure-based gas detectors from reaching the marketplace.

Results of the study were published November 28 in the journal Scientific Reports, published by Nature Publishing Group.

"We are very excited about this new discovery, which we think could lead to new commercial gas sensors," said Rensselaer Engineering Professor Nikhil Koratkar, who co-led the study along with Professor Hui-Ming Cheng at the Shenyang National Laboratory for Materials Science at the Chinese Academy of Sciences. "So far, the sensors have shown to be significantly more sensitive at detecting ammonia and nitrogen dioxide at room temperature than the commercial gas detectors on the market today."

Over the past decade researchers have shown that individual nanostructures are extremely sensitive to chemicals and different gases. To build and operate a device using an individual nanostructure for gas detection, however, has proven to be far too complex, expensive, and unreliable to be commercially viable, Koratkar said. Such an endeavor would involve creating and manipulating the position of the individual nanostructure, locating it using microscopy, using lithography to apply gold contacts, followed by other slow, costly steps. Embedded within a handheld device, such a single nanostructure can be easily damaged and rendered inoperable. Additionally, it can be challenging to "clean" the detected gas from the single nanostructure.