Seek a leak

If cars of the future are powered by fuel cells, as many predict
(see “A tankful of sunshine”),
they will undoubtedly require sensors to detect leaks of the
potentially explosive hydrogen fuel. Now scientists at France’s National Centre
for Scientific Research (CNRS) in Montpellier and the University of California
at Irvine have created a new type of hydrogen sensor using arrays of nanoscopic
palladium wires (Science, vol 293, p 2227). They’ve found that the arrays’
electrical resistance rapidly decreases when they are exposed to
hydrogen—and the decrease is proportional to the gas’s concentration, even
in the presence of…