Sustainability Energy

How a scientific breakthrough is making ‘green methane’

  • Scientists are using artificial photosynthesis to make methane out of carbon dioxide, water and sunlight.
  • A new device could be added to solar panels to essentially recycle fossil fuels.
  • The breakthrough comes as methane recently surpassed coal as the primary source of fuel for generating electricity in the United States.

With more trees on Earth than stars in the Milky Way galaxy, photosynthesis — how plants convert sunlight into energy — is happening all around us. And now researchers are leaning on that leaf-based process to recycle fossil fuels.

It’s being called “artificial photosynthesis,” a new approach that can make methane, the main component of natural gas, out of carbon dioxide, water and sunlight. Researchers are hoping to add the catalyst to solar panels, which could help make natural-gas-powered devices carbon neutral. The breakthrough has the potential to ease our dependency on fossil fuels as more places around the world are feeling the effects of climate change.

“Thirty percent of the energy in the U.S. comes from natural gas,” Zetian Mi, a University of Michigan professor who co-led the work, said in a release. “If we can generate green methane, it’s a big deal.”

The new work comes as U.S. natural gas demand reached an all-time high last year, and is expected to keep rising. Fracking is the latest — and controversial — method used for extracting natural gas, but the process has been linked to a rapid rise in global methane emissions that accelerate the pace of climate change.

Another promising aspect of the research from University of Michigan, McGill University and McMaster University, is that the team harnessed relatively large electrical currents with a device that is possible to mass produce.

The device is somewhat like a solar panel itself, studded with nanoparticles of copper and iron, according to the release from the University of Michigan. It can use the sun’s energy or an electrical current to break down the carbon dioxide and water. But, researchers also found a way for the device to run on electricity, potentially allowing it to operate in the dark.

Researchers say the design of the device is what is most important, since turning carbon dioxide into methane is a very difficult process.

“One million-dollar question is how to quickly navigate through the enormous materials space to identify the optimal recipe,” said Jun Song, a professor at McGill University who co-led the research.

The key to the device are the nanoparticles of copper and iron, which hold onto molecules by their carbon and oxygen atoms, buying time for hydrogen to make the leap from the water molecule fragments onto the carbon atom, researchers explained in a release.
The innovation is an “exciting advance,” Edward Sargest, a chemist and solar fuels expert at the University of Toronto who was not involved with the research, told Science Magazine.

“The advantage of generating methane is that the infrastructure to store, distribute, and utilize it is widely available already,” Sargest said.