"Catalytic condenser" lets cheap metals act like rare, expensive ones
It’s an unfortunate truth that many important chemical reactions require rare and expensive metals as catalysts. But now, scientists have developed a device that actively tweaks plain old aluminum to make it behave like other metals on the fly.
Platinum, palladium, rhodium and other metals are key drivers of reactions used to manufacture materials and chemicals in many industries. The problem of course is that these metals are hard to come by and as such can get very expensive, which drives up the cost of manufacturing equipment and processes, as well as the final products.
New research led by the University of Minnesota has found that by adding or removing electrons, common, cheap materials can be tuned to have some of the useful surface properties of expensive catalytic metals. A new device called a catalytic condenser can do just that.
“Atoms really do not want to change their number of electrons, but we invented the catalytic condenser device that allows us to tune the number of electrons at the surface of the catalyst,” said Paul Dauenhauer, lead researcher on the study. “This opens up an entirely new opportunity for controlling chemistry and making abundant materials act like precious materials.”
To adjust the number of electrons in a material, the catalytic condenser is made up of a series of thin films arranged in a stack. The top is a 4-nanometer-thick layer of alumina (aluminum oxide), which sits on a layer of graphene, with an insulator below that and a conductor on the bottom. When a voltage is applied to the graphene and conductor layers, a charge is induced in the alumina. This changes its surface properties, allowing it to act like a catalyst way above its pay grade.
The specific catalyst that the alumina can act like can be tweaked by tuning the voltage applied, the composition of the insulating layer, or including different additives in the active layer. The researchers say variations on these devices could be used in a range of industries, to perform different reactions as needed.
“We view the catalytic condenser as a platform technology that can be implemented across a host of manufacturing applications,” said Dan Frisbie, an author of the study. “The core design insights and novel components can be modified to almost any chemistry we can imagine.”
The research was published in the journal JACS Au.
Source: University of Minnesota