Morphology Is Key To Catalyst's Activity

By fashioning tricobalt tetraoxide into a nanorod, researchers have boosted the catalyst's activity and stability. Although Co₃O₄ is known to be good at catalyzing the oxidation of carbon monoxide, the compound is easily deactivated by trace amounts of moisture in normal feed gas. A group led by Wenjie Shen of China's Dalian Institute of Chemical Physics found that it could circumvent this deactivation by creating Co₃O₄ nanorods (Nature 2009, 458, 746). When adopting the nanorod shape, that catalyst takes on a molecular arrangement that preferentially exposes the material's active Co³⁺ sites. Shen's team found that the catalytic nanorods performed the oxidation well, even at temperatures as low as –77 ºC. Furthermore, the nanorods proved to be sufficiently stable in the presence of feed gases that contain large amounts of both water and carbon dioxide. The potential health risks associated with cobalt may keep these particular catalytic nanorods from use in widespread applications, such as air purification. But the researchers note that insights they've gleaned about how morphological control can influence a catalyst's properties "will most probably be applicable in the development of the next generation of highly efficient oxidation catalysts."