|Photo Credit via Pxhere|
Scientists around the world struggle to find a catalyst to convert carbon dioxide to carbon monoxide, a gas for usable energy, which does not initiate hydrogen evolution reaction, a competing reaction that takes over the conversion process. But scientists at the US Department of Energy have identified a possible new catalyst to convert CO2 into a usable energy. Unlike expensive catalysts, such as gold and platinum, the newly identified material is inexpensive and can more easily be found than noble metals.
“There are many ways to use CO. You can react it with water to produce energy-rich hydrogen gas, or with hydrogen to produce useful chemicals, such as hydrocarbons or alcohols. If there were a sustainable, cost-efficient route to transform CO2 to CO, it would benefit society greatly,” said Eli Stavitski, an author of the study and a scientist at Brookhaven National Laboratory at DOE.
Nickel is the material they identified as a better catalyst compared to noble metals. According to the scientists, they used single atoms of nickel, instead of noble metal nanoparticles, as a catalyst to convert CO2 into CO. Nickel is a silvery-white and lustrous metal known for its hardness and ductile properties. It is the fifth most common element on earth that can be obtained from the planet's crust. However, the metal is an ineffective catalyst in CO2 to CO conversion in bulk.
“One reason is that it performs HER very well and brings down the CO2 reduction selectivity dramatically. Another reason is that its surface can be easily poisoned by CO molecules if any are produced,” said Haotian Wang, a corresponding author of the study from Harvard University.
But single atoms of nickel produce the opposite effect. Instead of completing HER, atoms of the metal can convert the CO2 gas into CO. The logic is that energy found on the surface of bulk nickel is uniform, while a single atom offers different kinds of energy on its surface. The scientists were also able to tune nickel and suppress HER with the use of an atomically thin graphene sheet.
“To apply this technology to real applications in the future, we are currently aimed at producing this single atom catalyst in a cheap and large-scale way, while improving its performance and maintaining its efficiency,” added Wang.
Single atoms of nickel have a maximum of 97 percent efficiency to catalyze CO2 into CO.