Scientists at the American Department of Energy are in the process of developing a new palladium sensor that can detect leaks of the highly explosive gas hydrogen.

With hydrogen tipped to become increasingly widespread in everyday use through the rise in fuel cells a cheap, reliable sensor is deemed essential to ensuring the safety of the technology, particularly in the automotive industry.

At the Department of Energy's Sandia National Laboratories researchers have already developed one sensor for commercial use that has been bought by H2scan, which detects hydrogen in the air at concentrations as low as 30 parts per million.

However, Steve Huenemeier, president of H2Scan, told Wired News that the company's sensor 'would have to be made much smaller' for any automotive application and also cheaper.

As a result Wired News' Mark Baard reports To that end scientists at the Energy Department's Oak Ridge National Laboratory, in conjunction with DuPont, have designed a method for producing low-cost palladium sensors.

Sensors are made using a screen-printing device that applies a palladium-doped paste to an aluminium oxide substrate.

'You can cut the sensors out of a large sheet, much as a cookie cutter cuts shapes out of one large sheet of dough,' explained Tim McIntyre, a research physicist in the Sensor and Instrument Research Group at Oak Ridge.

Plans elsewhere in the country are investigating the possibility of using palladium nanowires to detect hydrogen, or even tainting the gas itself with an unmistakable stench.

Patrick Flynn and Michael Sprague, graduate students at Penn State, believe an odorant they have developed might even be benign enough to pass through hydrogen fuel cells, and across hydrogen sensors, without damaging the catalysts in either one.

At present DaimlerChrysler's F-Cell, a fuel-cell powered Mercedes-Benz sedan, has only one hydrogen sensor, which is located inside the passenger compartment.