A cobalt-based thin film could work as a catalyst that produces both hydrogen and oxygen from water to feed fuel cells.

The material is relatively inexpensive and could be extremely useful in the field of clean fuel, Rice University reported. It is predicted to be an extremely useful catalyst for the production of hydrogen through water electrolysis. A single layer of film thinner than a human hair could act as both the anode and cathode in an electrolysis device.

The recent study determined cobalt film is better at producing hydrogen than most modern materials and is a serious competitor for commercial platinum catalysts. The catalyst also proved to produce an oxygen evolution reaction on par with current materials.  

"It is amazing that in water-splitting, the same material can make both hydrogen and oxygen," said Rice lab chemist James Tour. "Usually materials make one or the other, but not both."

The researchers believe applying alternating current from wind or solar energy sources to cobalt electrolysis could become a greener source of hydrogen and oxygen.

"Here we can just alternate the current from positive to negative and back again, and hydrogen and oxygen are made with the same material," Tour said. "And the material itself is very easy to make." He said manufacturing the film is inexpensive and scalable.

To make their findings the researchers fabricated 500-nanometer films by anodyzing a cobalt film electrodeposited on a substrate. This concoction was baked for two hours in a phosphorus vapor, which converted it into "cobalt/phosphide/phosphate thin film" that remained porous.

The findings were published in a recent edition of the journal Advanced Materials.