I saw a demonstration of a gydrogen semi teactor trailer. Amazing. The technology works. The problem is lack f fueling stations.
The economics don't. The technology has not been a problem for a long time. We have used hydrogen in industrial process for decades. But it isn't even close in price to the energy from refined products.
Actually there are two major problems.
Extracting H2 costs energy and costs more than you get out.
H2 molecules are so small that Hydrogen leaks are almost impossible to avoid.
Other than that, it works fine