Can hydrogen alone be used as a fuel?
Hydrogen fuel cells which produce electricity from hydrogen and oxygen are over a hundred years old
https://www.thoughto.com/hydrogen-fuel-cells1991799

The recently introduced Toyota Mirai runs off a hydrogen fuel cell.
www.toyota.co.uk/mirai  as does the Hyundai ix35 and Honda Clarity

There aren't very many hydrogen filling stations in the UK which rather limits its appeal