Hope it’s true. Regardless, most of us will be using the internal combustion gas powered cars for at least a decade.
It’s a scam.
Water is a less excited state than free H2 and free O2 -— you get to H2 and 02 by adding energy, which is basically held in potential (less waste — typically heat) until combined back into water.
Somewhere in the loop (probably a charged membrane) there is energy going into the process, run by a battery of some sort.
Unless there is cold fusion (! itself probably a scam) going on, scam-o-rama.