I mean, you could create your own hydrogen at home. Hydrolysis machines exist, and are sometimes sold as medical devices to create pure oxygen from water. The other half of the output is hydrogen, which would be to be captured in a way that you can put it into your car.

It's an extremely inefficient way to power a car, though. Converting electricity to hydrogen and back to electricity (as most hydrogen fuel cell cars do) is a ton of loss. It's also a bunch of complexity, both mechanical and on the operator.