New Process Produces Iron Nanospheres

U.S. chemists say they’ve used a process that creates bubbles as hot as the surface of the sun to make hollow iron oxide nanospheres.

Hollow nanospheres of metals and other inorganic materials offer potential applications in drug delivery, electronic components, catalysts and other products.

Current methods of producing hollow hematite nanospheres require a time-consuming process and use of toxic hydrofluoric acid.

But now University of Illinois chemists Kenneth Suslick and Jin Ho Bang report creating a process that uses high-frequency sound waves focused into a solution containing an iron compound and carbon nanoparticles.

The sound waves create tiny bubbles in the liquid. The collapse of those bubbles causes intense local heating with temperatures estimated at 9,000 degrees Fahrenheit and forms iron spheres around the carbon nanoparticles.

On exposure to air, the iron rapidly oxidizes, which burns away the carbon core, leaving hematite spheres 1-1,000th the diameter of a red blood cell.

The new technology is to appear in the Feb. 28 issue of the Journal of the American Chemical Society.