Question: Would the water have to be a certain type of water? or could it be impure/drinking/sea water?

Jemma Rowlandson answered on 16 Jun 2014:

Hi!

Thanks for your question. At the moment to split water it has to be pure. You could use sea water but you’d have to remove the salt then purify it, which would be even more expensive!

The water has to be pure because the materials used to split water are easily broken down by impurities (and some are even broken down in pure water, they’re not that good yet).

Another reason for pure water is that we often use fuel cells in hydrogen cars. Fuel cells are great, they work a bit like a battery reacting hydrogen and oxygen to produce only electricity and water, again. The water is so pure from a fuel cell you actually could drink it!

The problem with fuel cells is that they stop working if there are any impurities in your hydrogen gas. If you use impure water to make the hydrogen then you will also get impurities in your gas. This would stop the fuel cell (and your car) in it’s tracks, meaning the hydrogen gas we use has to be very pure.