Don't know about this particular one but, up to now, they've all been snake oil. Mythbusters did a segment on these things a while back, and never got close to getting one to work.

The bubbles are neat, and it appears hydrogen is being generated. The problem is, unless there's another electrical power source besides the battery and alternator, it simply can't generate hydrogen fast enough. You just can't get past the Law of Thermodynamics. A battery and alternator will not generate enough power to drive a car.

Onward and upward,
airforce