Ultra-sensitive optical sensor can reduce risk from hydrogen

In the pursuit of clean and renewable energy, hydrogen plays an important role. But a major challenge to this transition is that the gas is explosive when mixed with air. For this reason, it is important to be able to detect a hydrogen leak as early as possible. Now, researchers at Chalmers University of Technology, Vrije University Amsterdam and Eindhoven University of Technology, have developed an optical sensor that can detect record low levels of hydrogen.

Hydrogen is considered an important part of the decarbonization of the heavy transport industry and around the world hydrogentrains, trucks and planes are being developed and deployed. Even in heavy industry, hydrogen is considered very important, for example for the production of fossil-free steel.

The risks of storing or using hydrogen are well known. Only four percent hydrogen in air is needed to form explosive mixtures (knallgas) that can ignite at the slightest spark. Therefore, it is important to have ultra-sensitive sensors to monitor for leaks and alarms at critical levels.

Safety is of paramount importance in the use of hydrogen

Together with Dutch colleagues, researchers in the Department of Physics at Chalmers University of Technology, Sweden, have now developed an optical hydrogen sensor that can detect record low hydrogen levels. Therefore, it joins the most sensitive sensors in the world. The new research results are presented in a paper on natural communication.

Chalmers Professor Christoph Langhammer said: “Safety is paramount in all hydrogen storage and use. If leaks are detected early, they can be remedied so you hopefully don’t have to stop. plant or vehicle operations”. , one of the main authors of the scientific paper.

AI technology leads the way

Optical hydrogen sensors consist of multiple metal nanoparticles that work together to detect hydrogen in the surrounding environment.

The approach to designing the new sensor is different from what has been done before. Instead of manufacturing a large number of samples and testing them individually to see which performs best, the researchers used advanced AI technology to create optimal interactions between particles based on distance. , their diameters and thicknesses. The result is a sensor that detects changes in hydrogen concentration as small as a few hundred thousand percent.

The secret behind the new sensor’s low detection limit is a combination of the usual patterned arrangement of particles on a surface and their finely tuned size. This turned out to be more favorable to the sensor’s sensitivity than the random particle arrangement used in sensors of the same type previously.

Christoph Langhammer’s team was previously able to present the world’s fastest hydrogen sensor. For him, it was clear that many different types of sensors were needed and they had to be optimized for specific applications.

“The technology around hydrogen has taken a giant leap forward and so today’s sensors need to be more precise and suitable for different purposes. Sometimes a very fast sensor is needed, sometimes a sensor is needed. operating in harsh chemical environments or at low temperatures. A single sensor design cannot meet all needs,” said Christoph Langhammer, who is also one of the founders of the new TechForH2 competency center. said.

Industry and academia in new hydrogen collaboration

The new center, led by Chalmers, brings together academia and industry to develop new hydrogen technology, focusing on the decarbonization of heavy-duty transportation systems. TechForH2 is led by Professor Tomas Grönstedt of Chalmers in the Department of Mechanical Engineering and Marine Science.

“When the research community and industry unite, that can take us to the next level, so that what we produce can be applied and meet the needs and challenges that exist in This applies to sensor development, as well as research related to the propulsion of heavy vehicles or aircraft using hydrogen gas,” said Tomas Grönstedt, who mentioned that an aircraft Electric power with a range of 500 km can increase the range to 3000 km if it is powered by hydrogen.

How optical hydrogen sensors work

The sensor the researchers have developed is based on an optical phenomenon, plasmons, which occurs when metal nanoparticles capture light and give the particles a distinct color. If the nanoparticles are made of palladium or a palladium alloy, their color will change as the amount of hydrogen in the surrounding environment changes, and the sensor can trigger an alarm if levels become severe.

To find the final match between the surface arrangement and geometry of the particles in the sensor, the researchers used an artificial intelligence algorithm called particle swarm optimization to achieve highest possible sensitivity to hydrogen exposure. Placing the particles in a very precisely defined conventional pattern turned out to be the answer.

Based on an AI design, an optimized optical hydrogen sensor was fabricated and verified as the first of its kind that can optically detect hydrogen in the “parts per billion” (250 ppb) range. ).

The new sensor is based on an optical phenomenon called “plasmon”, which occurs when metal nanoparticles captures light and gives the particles a distinct color. This color changes as the amount of hydrogen in the surrounding environment changes and the sensor can trigger an alarm at a critical level.