Heated particles shift shape and become highly active catalytically
A Northwestern University research team has developed a new method for making highly desirable catalysts from metal nanoparticles that could lead to better fuel cells, among other applications. The researchers also discovered the method can take spent catalysts and recycle them into active catalysts.
Made mainly of precious metals, these coveted catalysts are shaped like gems. 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 methodology takes basic metal precursors, and, using heat and stabilizing trace elements, 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 method is a general one; the study shows it works with five monometallic nanoparticles and a library of bimetallic nanoparticles, spanning seven different metals, including platinum, cobalt and nickel.
“Many of these precious metals are responsible for catalyzing some of the most important chemical transformations used in the chemical, oil and fuel cell industries,” said Chad A. Mirkin, the George B. Rathmann Professor of Chemistry in the Weinberg College of Arts and Sciences, who led the research.
“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,” Mirkin said.