Scientists have discovered a method to control the gas-phase-selective catalytic combustion of methane, so that the reaction produces ethylene at room temperature and formaldehyde at lower temperatures.
Being able to catalyse these reactions — at or below room temperature — may lead to significant cost savings in the synthesis of plastics, synthetic fuels and other materials.
‘The beauty of this process is that it allows us to selectively control the products of this catalytic system so that if one wishes to create formaldehyde, and potentially methyl alcohol, one burns methane by tuning its reaction with oxygen to run at lower temperatures, but if it’s ethylene one is after, the reaction can be tuned to run at room temperature,’ said Prof Uzi Landman, director of the Center for Computational Materials Science at Georgia Tech, who conducted the research with counterparts at the University of Ulm.
Last year, a team that included theorists Landman and Robert Barnett from Georgia Tech and experimentalists Thorsten Bernhardt and Sandra Lang from the University of Ulm found that, by using gold dimer cations as catalysts, they could convert methane into ethylene at room temperature.
This time, the team has discovered that, by using the same gas-phase gold dimer cation catalyst, methane partially combusts to produce formaldehyde at temperatures below 250 kelvin or -9°F.
What’s more, in both the room-temperature reaction-producing ethylene and the formaldehyde-generation colder reaction, the gold dimer catalyst is freed at the end of the reaction, thus enabling the catalytic cycle to repeat.