Hydrogen & Fuel Cells
- Category: Hydrogen & Fuel Cells
05 Sep 2012
- Published on Wednesday, 05 September 2012 09:04
- Hits (1765)
Cobalt could be the key to providing better and cheaper catalysts for hydrogen production.
Ancient crafts workers prized cobalt-based pigments for their ability to lend a blue tint to ceramics, glass works or metal wear, the most common example being the blue and white porcelain prized by the Chinese during the Tang, Song and Ming dynasties.
Today’s Caltech chemists are hoping to harness another property of cobalt and cobalt compounds – its ability to trigger the electrolysis of water. Electrolysis is commonly known as water splitting, where water is separated into its composite elements oxygen and hydrogen.
Efficient and economical water splitting is key to the use of hydrogen as a sustainable fuel and power source. In order to achieve this, robust and cost-efficient catalysts must be developed.
The most common catalysts are platinum or platinum-based materials, but platinum is a rare and expensive material. Cobalt catalysts are a less costly alternative but it can’t match the performance of platinum as of yet.
The Caltech researchers decided to get a closer look at cobalt to determine the mechanism or chemical pathway by which cobalt triggers the water splitting reaction.
Caltech postdoctoral scholar Smaranda Marinescu was able to add a set of ligands to cobalt, slowing down the reaction to the point where they could observe it using a nuclear magnetic resonance spectroscopy and see it happen in real time.
They found that a key point in the reaction was cobalt gaining an extra electron, forming a compound called cobalt(II) hydride.
"We now know that you have to put another electron into cobalt catalysts in order to get hydrogen evolution,” said Harry Gray, professor of chemistry and the senior author of a paper describing the team’s findings.
"Now we have to start looking at designs with ligands that can accept that extra electron or those that can make atomic cobalt, which already has the extra electron," added Mr. Gray.
The work was supported by the National Science Foundation Center for Chemical Innovation in Solar Fuels as well as Chevron Phillips Chemical. – EcoSeed Staff