Re:First water car is already a reality: 1000km of autonomy ...
by mojomark on Sunday September 08, 2024 @05:34PM
(#41483419)
I was not referring to electrolysis, I was referring to the chemical reaction between water and certain Aluminum compounds to liberate H2 (which creates Aluminum oxide and other byproducts, and if you want to recover the Aluminum catalyst, you must add energy to remove the Oxygen from the Aluminum oxide (i.e. "re-energizing" the catalyst so that it can be used again in a reaction with water). Pretty straight forward.
That is NOT a catalyst, as roelschroeven correctly commented.
Otherwise a rechargeable battery would be a "catalyst" because it too needs to be re-energized or replaced.
What a catalyst does is lower the activation barrier between two states, without providing net energy. Getting H2 from H2O, i.e. electrolysis, requires adding energy. We know this because fuel cells work in the other direction to produce power, and entropy always increases.