I have always thought that fuel such as petrol, diesel, etc.. are getting burnt to move the pistons in the car (I am not bringing physics). Why not hydrogen be used as a fuel but I know the incident about the Hindenburg disaster but the same thing could happen if the Hindenburg was filled with petrol. So both are combustible and that's what we want. Petrol and hydrogen do the same job what does he want?. When hydrogen is burnt there won't be any smoke so it saves the environment. PS: This is just to make this question a bit understandable I have mentioned the word "Alone" in the question.
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