Hydrogen doesn't buy you that much additional lifting power.
Air is about 1.2kg/m^3 at STP, so that's the theoretical maximum you can lift with a cubic meter of gas bag. (And you can only get that value if you could somehow hold a vacuum, of course.)
Hydrogen is about 0.09kg/m^3 at STP, so you can lift about 1.1kg/m^3. Helium is about 0.18kg/m^3, so you can lift about 1kg/m^3. Helium is twice as dense, but that only costs you about 10% of your lifting power since both are so light compared to air.
I see no reason you couldn't use hydrogen, but I don't know if anyone would want to take the risk. (Specific flaws of the Hindenburg aside, hydrogen is explosive across a distressingly wide range of mixture ratios with air.) If you did use hydrogen, I think the main motivation would be avoiding the use of scarce helium, not the minor increase in lift capacity.
But still critical enough to make it impractical. How would you do maintenance on a hydrogen airship without risking the people doing the maintenance? And you'd never be able to fly over populated areas.
Air is about 1.2kg/m^3 at STP, so that's the theoretical maximum you can lift with a cubic meter of gas bag. (And you can only get that value if you could somehow hold a vacuum, of course.)
Hydrogen is about 0.09kg/m^3 at STP, so you can lift about 1.1kg/m^3. Helium is about 0.18kg/m^3, so you can lift about 1kg/m^3. Helium is twice as dense, but that only costs you about 10% of your lifting power since both are so light compared to air.
I see no reason you couldn't use hydrogen, but I don't know if anyone would want to take the risk. (Specific flaws of the Hindenburg aside, hydrogen is explosive across a distressingly wide range of mixture ratios with air.) If you did use hydrogen, I think the main motivation would be avoiding the use of scarce helium, not the minor increase in lift capacity.