Metallic molecules

Emory University researchers have created stable multiple chemical bonds between oxygen and platinum, a development that could have an impact for designers of fuel cells and catalytic converters.

Chemical bonds between metals and oxygen are known as metal-oxo species, and are found in a multitude of molecules and materials. They are dominant in the chemistry, geology and biology of many metal elements, especially during oxidation.

However, metal-oxo species become increasingly less stable as one moves from left to right on the periodic table. Until this work, the researchers say that attempts to create metal-oxo species with elements such as gold, platinum, silver, iridium and rhodium had been unsuccessful.

“The existence of such metal-oxo complexes has been presented and debated in many public forums but never realized until this research. Since this metal-oxo is a unique compound, both its physical properties and its chemical reactivities should provide new insights and break new ground,” says principal investigator Craig Hill, Goodrich C. White Professor of Chemistry at Emory.

Stable compounds of platinum and oxygen could be centrally important to the operation of automobile catalytic converters. Catalytic converters use a platinum catalyst to interact with oxygen in the air to form highly reactive platinum-oxygen intermediates and other species that fully combust the partially burned fossil fuels emanating from the internal combustion engine.

The platinum-oxo compound is expected to be a model for these highly elusive platinum-oxygen intermediates and, as such, could provide key insights into improving existing technology.

One important and growing technology where the platinum-oxo unit may also be key is fuel cells. The electrodes in these cells are frequently based on platinum, and in some instances the reaction of platinum with oxygen is central to their operation.

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