Is there oxygen on Mars? Technically yes, but it’s nothing like the amount we have on Earth. So breathing is out of the question. However, there IS a lot of carbon dioxide (CO2) on Mars. Now a new technology — MOXIE — has proven that we can convert Martian CO2 into oxygen for use by future explorers.
Mars has oxygen but not very much and definitely not enough for you to just go out and breathe on the surface of Mars. The density of the oxygen on Mars is about 1/10,000th of what we have here on Earth. But Mars’ atmosphere does have a lot of carbon dioxide — about 500 times more CO2 than oxygen.
if we want to harvest oxygen on Mars for use by future explorers or launch systems, a better way might be to pull some of it out of the CO2 and use that instead. So that’s where MOXIE comes in. MOXIE is a technology on NASA’s Perseverance rover, and it has proven for the very first time that we can extract oxygen from the carbon dioxide in the Martian atmosphere. It’s a tech demo so it only produces a small amount of oxygen. But for future human exploration, we would need to sendna scaled-up version, maybe 200 times larger than the current MOXIE. if such a system were landed on Mars, some of this would provide oxygen for the astronauts to breathe but most of it would be used as rocket propellant to get astronauts to the surface of Mars and back to Earth. So is there oxygen on Mars? Not much, but that’s okay because we can make it ourselves.
For more detail please read NASA