New York, Sep 25 (IANS): Chemical engineers in the US are developing new ways to convert greenhouse gases to fuel to address climate change and get astronauts home from Mars.

Researchers at the University of Cincinnati used a carbon catalyst in a reactor to convert carbon dioxide into methane. Known as the "Sabatier reaction" from the late French chemist Paul Sabatier, it's a process the International Space Station uses to scrub the carbon dioxide from air the astronauts breathe and generate rocket fuel to keep the station in high orbit.

The Martian atmosphere is composed almost entirely of carbon dioxide. Astronauts could save half the fuel they need for a return trip home by making what they need on the red planet once they arrive, said Jingjie Wu, Assistant Professor at UC College of Engineering and Applied Science.

"It's like a gas station on Mars. You could easily pump carbon dioxide through this reactor and produce methane for a rocket," Wu said. Wu aims to recycle carbon dioxide to achieve carbon neutrality.

For the study, published in the journal Nature Communications, the team experimented with different catalysts such as graphene quantum dots -- layers of carbon just nanometres big -- that can increase the yield of methane.

Wu said the process holds promise to help mitigate climate change. But it also has a big commercial advantage in producing fuel as a by-product.

Wu's students also used different catalysts to produce not only methane but ethylene. Called the world's most important chemical, ethylene is used in the manufacture of plastics, rubber, synthetic clothing and other products.

Synthesising fuel from carbon dioxide becomes even more commercially viable when coupled with renewable energy such as solar or wind power, Wu said.

"Right now we have excess green energy that we just throw away. We can store this excess renewable energy in chemicals," he said.

The process is scalable for use in power plants that can generate tons of carbon dioxide. And it's efficient since the conversion can take place right where excess carbon dioxide is produced.

Wu added advances in fuel production from carbon dioxide make him more confident that humans will set foot on Mars in his lifetime.