Nickel dopants could improve sustainable production of ethylene oxide, a chemical widely used in industrial manufacturing.
Plastics, textiles, detergents, adhesives and antifreeze all have something in common: They were made using ethylene oxide. This colorless gas, a chemical building block in the industrial production of many materials, is itself produced by reacting oxygen with ethylene. However, maximizing the amount of ethylene oxide produced poses unique challenges.
Adding chlorine increases the efficiency of ethylene oxide production by 25 percent. But chlorine, which is corrosive to metal equipment, has its own drawbacks. Writing in Science, researchers at the University of California, Santa Barbara (UCSB), Tufts University, Brookhaven National Laboratory and Tulane University identified nickel as a promoter that can enhance the selectivity of the silver catalyst by about 25 percent, roughly the same amount as chlorine, but with fewer downsides. The team studied the interaction of nickel with the silver catalyst using X-rays from the Stanford Synchrotron Radiation Lightsource (SSRL) at the Department of Energy’s SLAC National Accelerator Laboratory.
“From an environmental standpoint, if you remove chlorine, that’s one less toxic and corrosive material out of the process stream,” said Adam Hoffman, a staff scientist at SLAC who contributed to this work. “And if you can improve a catalyst’s activity to a target chemical, it improves the sustainability of the process as a whole.”
Charles Sykes, a chemist at Tufts University who led the effort, said it also makes financial sense. “Every one percent increase in the efficiency of the process saves around $200 million annually,” he said.
If you remove chlorine, that’s one less toxic and corrosive material out of the process stream.
Adam Hoffman SLAC Staff Scientist
A more selective catalyst doesn’t only maximize the amount of product, it is also more efficient overall. Post reaction, ethylene oxide must be separated from the side products and residual reactants, a process that requires additional energy inputs. If the reaction is more selective to ethylene oxide to begin with, it is easier to purify.
Read more on SLAC website
Image: A computer-generated image showing single nickel (Ni) atoms embedded in silver, used to enable efficient production of ethylene oxide.
Credit: Elizabeth Happel/Tufts University