This Zero-Power Leak Sensor Could Help Deliver a Future of Clean, Safe Hydrogen Power
A palladium cantilever sits passively, until as little as 0.3% hydrogen concentrations are detected — then can trigger an alarm.
Researchers from Yonsei University and the Kumoh National Institute of Technology have come up with a new way to detect leaks in hydrogen storage and transport facilities — with a switch that draws absolutely no power.
"Our approach turns the sensor into a true sleeping watchman," authors Daeyeon Koh, Eunhwan Jo, and Jongbaeg Kim say of their work. "It consumes power only when hydrogen is actually present, which is a game-changer for remote monitoring stations where changing batteries every few months isn’t practical. The fabrication method itself is surprisingly simple — we use water, alcohol, and electrospun polymer fibers instead of toxic photoresists and developers. That means lower environmental impact and lower cost, which matters if you want to deploy thousands of these sensors across a hydrogen pipeline or a fueling station."
Hydrogen is in the running to be the fuel of the future, produced via electrolysis using renewable energy and consumed at the point of use while producing nothing but water vapor as a byproduct. There are a few kinks to work out, still, not least of which is storage and transportation — with hydrogen being rather excitable, with ignition possible with as little as 4% hydrogen to air. Existing leak sensors draw very little power, but monitoring a distribution pipeline may require thousands or even tens of thousands of sensors.
The solution is to find a way to monitor for leaks that doesn't require power, something researchers have already managed using chemical-mechanical and microelectromechanical systems (MEMS) approaches; the former has proved unreliable, while the latter requires expensive photolithographic production processes that use hazardous chemicals.
The system proposed by Koh, Jo, and Kim, however, resolves those problems, with a production process that requires no nasty chemicals or photolithography. Made from chromium and palladium deposited on electrospun PEO nanofibers, the sensor is mechanical in nature: the palladium absorbs hydrogen and expands just enough to bend a cantilever shape downwards, completing a circuit and triggering an alarm. Testing showed no reaction to non-hydrogen gases, only marginal responses to humidity, a sub-40 second response time, and the ability to detect concentrations of hydrogen in air as low as 0.3% — well below the level at which ignition is possible.
The team's work has been published in the journal Microsystems & Nanoengineering, under open-access terms.