In air: hot nitrogen (~80% of air) + oxygen present -> some nitrogen will react even though it's not the fuel input. Not much different from burning other stuf

In air: hot nitrogen (~80% of air) + oxygen present -> some nitrogen will react even though it's not the fuel input. Not much different from burning other stuffs in air, really (gasoline / diesel included). Of course the burn conditions have a big effect. And cleanup after the burn (catalysts) is possible. But imho the more sensible thing would be to input the H2 into a fuel cell.