New electrolyzer could make hydrogen and oxygen out of salty Mars water
Weight is a premium on space launches, so the less we have to take with us, the better. Now, engineers at Washington University in St. Louis have developed a new electrolysis device that may be able to convert very salty Martian water into breathable oxygen and hydrogen for fuel.
As you may remember from high school science class, water electrolysis is the process of using electricity to split water into its constituent atoms of hydrogen and oxygen. These gases can then be collected for use so, in theory, electrolysis could be a way for astronauts to produce their own oxygen and hydrogen on the Red Planet.
The problem is, it doesn’t work too well on brackish water, which is all you’d find on Mars. The high salt content would need to be reduced first, which is a difficult process in that less-than-hospitable alien environment.
So for the new study, the researchers developed a new electrolysis system that can work on briny water and operate in the extreme cold of the Martian atmosphere. The key change is in the two electrodes – the team created an anode out of lead ruthenate pyrochlore, and a cathode out of platinum on carbon.
To test the new electrolyzer design, the team simulated the Martian atmosphere, which required cooling things down to a chilly -36 °C (-32.8 °F) – and it worked. The team says that for the same input power, the new electrolyzer produces over 25 times more oxygen than MOXIE, the instrument onboard the Perseverance rover that will wring oxygen out of carbon dioxide in the air.
While the technology has intriguing potential applications for astronauts, it’s worth keeping in mind that water on Mars is a pretty rare commodity, so it would probably be better used for drinking – although that will also require removing the salt first. Instead, the tech could find use here on Earth first.
“Having demonstrated these electrolyzers under demanding Martian conditions, we intend to also deploy them under much milder conditions on Earth to utilize brackish or salt water feeds to produce hydrogen and oxygen, for example, through seawater electrolysis,” says Pralay Gayen, co-first author of the study.
The research was published in the journal Proceedings of the National Academy of Sciences.