The future of hydrogen as a transportation fuel has numerous hurdles to climb, but one of the most basic is just how it gets used in an engine.
Most of the focus has been on the debate between combustion — using hydrogen in an internal combustion engine engineered for it — or injecting it into an onboard storage tank where it is then fed into a fuel cell. The fuel cell generates electricity and the waste product is water.
Both have environmental issues. Combustion of hydrogen creates problematic...
https://www.freightwaves.com/news/amogy-dont-burn-hydrogen-split-ammonia-instead