New Catalyst could Dramatically Cut Methane Pollution from Millions of Engines

Researchers demonstrate a way to remove the potent greenhouse gas from the exhaust of engines that burn natural gas. Today’s catalysts for removing unburnt methane from natural-gas engine exhaust are either inefficient at low, start-up temperatures or break down at higher operating temperatures. A new single-atom catalyst solves both these problems and removes 90% of the methane.

Individual palladium atoms attached to the surface of a catalyst can remove 90% of unburned methane from natural-gas engine exhaust at low temperatures, scientists reported today in the journal Nature Catalysis.

While more research needs to be done, they said, the advance in single atom catalysis has the potential to lower exhaust emissions of methane, one of the worst greenhouse gases, which traps heat at about 25 times the rate of carbon dioxide.

Researchers from the Department of Energy’s SLAC National Accelerator Laboratory and Washington State University showed that the catalyst removed methane from engine exhaust at both the lower temperatures where engines start up and the higher temperatures where they operate most efficiently, but where catalysts often break down.

“It’s almost a self-modulating process which miraculously overcomes the challenges that people have been fighting — low temperature inactivity and high temperature instability,” said Yong Wang, Regents Professor in WSU’s Gene and Linda Voiland School of Chemical Engineering and Bioengineering and one of four lead authors on the paper.

A growing source of methane pollution

Engines that run on natural gas power 30 million to 40 million vehicles worldwide and are popular in Europe and Asia. The natural gas industry also uses them to run compressors that pump gas to people’s homes. They are generally considered cleaner than gasoline or diesel engines, creating less carbon and particulate pollution.

However, when natural-gas engines start up, they emit unburnt, heat-trapping methane because their catalytic converters don’t work well at low temperatures. Today’s catalysts for methane removal are either inefficient at lower exhaust temperatures or they severely degrade at higher temperatures. https://www6.slac.stanford.edu/news/2023-07-20-new-catalyst-could-dramatically-cut-methane-pollution-millions-engines