A doctoral student from the Department of Mechanical, Aerospace and Nuclear Engineering at Rensselaer Polytechnic Institute, one of the America’s oldest technological research university, Fazel Yavari has developed a new sensor that detects extremely small quantities of hazardous gases. The innovation is made from 3-D foam of the world’s thinnest material—grapheme.
“This sensor is durable, inexpensive to make, and opens the door to a new generation of gas detectors for use by bomb squads, defense and law enforcement officials, as well as applications in industrial settings” According to Yavari who’s project is on “High Sensitivity Detection of Hazardous Gases Using a Graphene Foam Network.
Detecting trace amounts of hazardous gases present within air is a critical safety and health consideration in many different situations, from industrial manufacturing and chemical processing to bomb detection and environmental monitoring. Conventional gas sensors are either too bulky and expensive, which limits their use in many applications, or they are not sensitive enough to detect trace amounts of gases. Also, many commercial sensors require very high temperatures in order to adequately detect gases, and in turn require large amounts of power.
Yavari’s project detailed the problems faced by researchers in having influence in the complete usage of nano-materials for gas detection. In theory, individual nanostructures like graphene, an atom-thick sheet of carbon atoms arranged like a nanoscale chicken-wire fence are extremely sensitive to chemical changes, however, creating a device based on a single nanostructure is costly, highly complex, and the resulting devices are extremely fragile, prone to failure, and offer inconsistent readings.
Yavari has overcome these obstacles and created a device that brings together the high sensitivity of a nanostructured material with the durability, low price, and ease of use of a macroscopic device. His new graphene foam sensor, about the size of a postage stamp and as thick as felt, works at room temperature, is considerably less expensive to make, and still very sensitive to tiny amounts of gases. The sensor works by reading the changes in the graphene foam’s electrical conductivity as it encounters gas particles and they stick to the foam’s surface. Another benefit of the Yavari’s device is its ability to quickly and easily remove these stuck chemicals by applying a small electric current.
The new graphene foam sensor has been engineered to detect the gases ammonia and nitrogen dioxide, but can be configured to work with other gases as well. Ammonia detection is important as the gas is commonly used in industrial processes, and ammonia is a byproduct of several explosives. Nitrogen dioxide is also a byproduct of several explosives, as well as a closely monitored pollutant found in combustion exhaust and auto emissions. Yavari’s sensor can detect both gases in quantities as small as 0.5 parts-per-million at room temperature.