Astronauts planning trips to Mars might one day be able to produce their own rocket fuel using a new technique called electrochemical reduction, as suggested by a recent study. This method involves transforming carbon dioxide from the Martian atmosphere into methane, a flammable gas that can be used as liquid fuel for rockets. The process uses electrolysis, which is a method of using electricity to drive chemical reactions that produce useful fuels and chemicals. The research was led by Ahmed Badreldin, a chemical engineer from the University of Mississippi, and included Carter Racine, a mechanical engineering Ph.D. student at Texas A&M University. The team developed a special type of copper catalyst, just a few nanometers in size, which is infused with nitrogen. This catalyst can produce nearly pure methane, which is crucial for use in rocket engines. Earlier methods of electrochemical reduction often produced methane along with many other byproducts, requiring complicated and heavy equipment to separate the methane — something that would be impractical on Mars. Mars has a very thin atmosphere, but it is mostly made up of carbon dioxide, which makes up about 96% of the air. This provides a ready source of material for the process. Being able to produce methane on Mars would significantly cut the need to bring fuel from Earth, which is both expensive and logistically difficult due to the high energy required to launch heavy loads from Earth's gravity. This technique could also have applications on Earth, where it might be used to create methane from carbon dioxide in the atmosphere, potentially reducing the need for fossil fuels. However, using carbon dioxide to make methane for fuel doesn't reduce the total amount of carbon dioxide in the atmosphere, as it is released back when the methane is burned. Scientists are now looking into ways to go beyond simply recycling carbon dioxide and instead develop methods that store carbon for longer periods, creating a net-negative impact on carbon emissions. The findings of this study were published in the journal ACS Catalysis in April.