CHICAGO, Sept. 13 (Xinhua) -- Northwestern University (NU) researchers have developed a new method to make highly desirable catalysts from metal nanoparticles that could lead to better fuel cells, among other applications.
The method works with five monometallic nanoparticles and a library of bimetallic nanoparticles, spanning seven different metals, including platinum, cobalt and nickel.
Using heat and stabilizing trace elements, the methodology rapidly transforms their shape into structures that are highly active catalytically. Commercial products such as fuel cells, important sources of clean energy, rely on such catalysts.
The new catalysts, called high-index facet nanoparticle catalysts, are shaped like gems, and each particle has 24 different faces that present atoms at the surface in ways that make them more catalytically active than those available commercially. The researchers found their platinum catalysts were 20 times faster than the commercial low-index form for the formic acid electrooxidation reaction based upon platinum content.
"Platinum in the high-index facet form is different and better than it is in other nanoparticle forms," said Chris Wolverton, co-author of the study and a professor of materials science and engineering at NU's McCormick School of Engineering.
The new catalysts can be made in mass and without the use of ligands, which can compromise catalytic activity.
"We not only can prepare commercially desirable catalysts, but we can recycle used fuel cell catalysts into the most active forms. Catalysts slowly degrade over time and change, so the fact that we can reclaim and reactivate these catalysts made of expensive materials is extremely valuable," said Chad A. Mirkin, a professor of chemistry at NU's Weinberg College of Arts and Sciences, who led the research.
The process that can both create new catalysts and recycle spent catalysts is fast and scalable. The technology may not be far away from being used commercially.
Catalysis contributes to more than 35 percent of the world's gross domestic product, according to the American Chemistry Council.
The study is to be published Friday in the journal Science.
