Gas sensing
employees, and the app can be configured with many kinds of communication devices.”
ALARMS AND RESPONDERS The solution provides users with comprehensive protection, with alarms triggered in the following situations: ‘SOS alarms’ allow workers to initiate alarms on their smartphone or via a small external Bluetooth-connected key fob; ‘Person- down detection’ automates the trigger of an alarm when a worker becomes incapacitated; and,‘Gas alarms’ raise alerts when dangerous levels of gas are detected.
All alarms are relayed to central and local response teams in seconds, providing crucial information to responder teams, including the worker’s name, precise location, telephone number and details of any dangerous gases present. Responders can collaborate using Push-to-Talk (PTT) technology, enabling them to coordinate their actions in real-time to support colleagues quickly and with the appropriate safety equipment, such as emergency escape sets.
MEETING SUSTAINABILITY TARGETS Since this integrated solution enables organisations to make use of their existing Bluetooth-enabled Dräger gas detectors and smartphones, it eliminates the need for organisations to invest in new devices. This not only reduces the number of devices workers have to carry, but saves money and minimises electronic waste too.
“Lone worker safety is an important issue in the field of gas detection, and we are delighted to bring this new solution to market through our partnership with Isle Systems and ANT Telecom.” comments Becca Dodds, marketing manager, Mobile Gas Management, Draeger Safety UK. “In today’s high-risk work environments, ensuring the safety of lone workers and maintaining robust gas detection protocols are critical priorities. This new integrated solution will help deliver a comprehensive, flexible, cost-effective approach to safety that protects workers from both gas hazards and lone- working risks while also enabling organisations to utilise their existing equipment, reducing costs and environmental impact.
“In turn, this also ensures rapid alarm response with centralised and local team coordination. One of the key benefits is the flexibility it offers – many of our customers have lone workers with a portion of them requiring gas monitoring. In these instances, all employees can use the same lone worker solution, whilst only investing in the gas detectors they actually need. We are proud to be involved in this project and look forward to rolling this solution out to businesses across the globe.”
Draeger Safety UK
www.draeger.com/en_uk/Home Instrumentation Monthly June 2025 G
MODIFYING GRAPHENE WITH PLASMA TO PRODUCE BETTER GAS SENSORS
as sensors are essential for personal safety and environmental monitoring, but traditional sensors have limitations in sensitivity and energy efficiency. Now, researchers from Japan have developed an improved gas-sensing technology by treating graphene sheets with plasma under different conditions, creating structural and chemical defects that enhance ammonia detection. These functionalized graphene sheets exhibited superior sensing performance compared to pristine graphene, potentially paving the way for wearable gas detection devices for everyday use.
Gas sensing technologies play a vital role in our modern world, from ensuring our safety in homes and workplaces to monitoring environmental pollution and industrial processes. Traditional gas sensors, while effective, often face limitations in their sensitivity, response time, and power consumption. To account for these drawbacks, recent developments in gas sensors have focused on carbon nanomaterials, including the ever-popular graphene. This versatile and relatively inexpensive material can provide exceptional sensitivity at room temperature while consuming minimal power. Thus, graphene holds the potential to revolutionize gas detection systems. Against this backdrop, a research team led by associate professor Tomonori Ohba from the Graduate School of Science, Chiba University, Japan, explored a promising avenue to improve graphene’s sensing properties even further. As reported in their latest paper, which was published in ACS Applied Materials & Interfaces, the team investigated how and why graphene sheets treated by plasma with different gases can lead to enhanced sensitivity for ammonia (NH₃), a toxic compound.
The researchers produced graphene sheets and applied a plasma treatment to them under argon (Ar), hydrogen (H₂), or oxygen (O₂) environments. This treatment “functionalized” graphene, meaning that it modified the surface of the graphene sheets by attaching specific chemical groups and creating controlled defects, serving as additional binding sites for gas molecules like NH₃. After treatment, the researchers employed a variety of advanced spectroscopic techniques and theoretical calculations to shed light on the precise chemical and structural changes the graphene sheets underwent.
The team found that the gas used during plasma treatment led to the creation of different types of defects on the graphene sheets. “The O₂ plasma treatment induced oxidation of the graphene, producing graphoxide, whereas the H₂ plasma treatment induced hydrogenation,
producing graphane,” explains Assoc. Prof. Ohba, “Spectroscopic analysis suggested that graphoxide had carbon vacancy-type defects, graphane had sp3-type defects, and Ar-treated graphene had both types of defects.” To clarify, an sp3-type defect is a structural change where a carbon atom in graphene shifts from having three bonds in a flat plane to forming four bonds in a tetrahedral arrangement, often due to hydrogen atoms attaching to the surface.
Interestingly, introducing these defects into the graphene sheets greatly enhanced their performance for sensing NH₃. Since NH₃ binds more easily to defects rather than to pristine graphene, the electrical conductivity of functionalized sheets changed more noticeably when exposed to NH₃. This property can be leveraged in gas-sensing devices to detect and quantify the presence of NH₃. Graphoxide, in particular, exhibited the greatest changes in sheet resistance (the inverse of conductivity) when exposed to NH₃—these changes were as high as 30 per cent. Worth noting, the team tested whether functionalized graphene sheets could withstand repeated exposure to NH3 without degrading their gas-sensing performance. Although some irreversible changes in sheet resistance were observed, some significant changes were fully reversible and cyclable. “The results showed that functionalizing graphene structures with plasma generated noble materials with a superior NH3 gas-sensing performance compared with pristine graphene,” concludes Assoc. Prof. Ohba. Overall, this study serves as an important stepping stone toward next-generation gas-sensing devices. Excited about their findings, Assoc. Prof. Ohba remarks: “As graphene is among the thinnest possible sheets with gas permeability, the functionalized graphene sheets developed in this work could be used in daily wearable devices. Thus, in the future, anyone would be able to detect harmful gases in their surroundings.” Hopefully, further work in this field will make this vision a reality and push graphene- based technology forward.
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