It seems as posssible thing. What they actually do is producing of good old "Synthesis gas" - mixture of CO and H2.
Same mix could be produced by exposing of strongly heated carbon to water vapour as follows:
C + H2O= CO + H2
It is ok up to this point.
The only question i was not able to find answer for was the quality of the carbon rods and, consequently, their cost.
Say, you want to produce such quantity of CO/H2 mix that would be equivalent by it's energy to 1 liter of gasoline.
You would need to burn relatively big amount of grafite in this plasma generator. Crude , cheap carbon (coal or grafite) is contents a lot of impurities. Besides you must keep some distanse between electrodes to get the whole invention properly operated. Consequently it have to be pure carbon RODS and not ,say lumps of cheap freshly mined coal.
They have presented nice tables showed that no corrosive gases (like NO, NO2,SO2) could be formed during operation of the device, but still all their data is based on using of pure carbon.