Adsorbed platinum Catalyst improves fuel cell performance

Chemists in the US have developed a new catalyst that could help in a key reaction used to generate hydrogen for fuel cells.
The water-gas shift (WGS) reaction is used in industry to help purify the hydrogen that is generated as a by product in the reforming of natural gas. In the reaction, residual carbon monoxide in the hydrogen is combined with steam in the presence of a catalyst to produce hydrogen and carbon dioxide. The process purifies the hydrogen gas to a level where it can be used in fuel cells.
However, none of the catalysts currently used in the WGS reaction are ideal. Copper based catalysts essentially do the job, but copper can spontaneously ignite in air, a dangerous property given that air is often used in fuel-cell operation. One alternative has been platinum, yet on its own this element is prohibitively expensive. To stand any chance of commercial viability it must be prepared in tiny particles supported by the rare earth oxide ceria. Unfortunately, ceria is only found in a few places and its supply is restricted. But platinum could be used as a catalyst for the water gas shift reaction.
Researchers at Tufts University and Harvard University, Massachusetts, have been investigating other ways to make platinum viable as a WGS reaction catalyst. By chance, they discovered that alkali metal ions like sodium or potassium can activate fine platinum particles when they are adsorbed on alumina or silica. When they examined the structure, they found extra active oxygen species that seemed to help the platinum complete the reaction cycle. The researchers claim that this finding will surely be a stepping-stone to new and more efficient catalytic formulation in particular with a view at reducing the quantity of platinum needed to obtain an active catalyst.