Nano-sized machinery makes me shiver. Thinking at a molecular and atomic level when speaking about technology makes me wonder even more. Even if I consider myself a logic person, extremely small and extremely large objects impress me.
Fuel cells, the converters of hydrogen into electricity, use nano-sized platinum particles as catalysts for the reduction of oxygen. They have usually been expensive and inefficient, creating far less impact on the auto industry than expected.
Japanese scientists have created sub-nano scale platinum clusters with high catalytic activity for use in fuel cell applications. The tiny catalyst particles – the smallest of which contain just 12 atoms in total – could help to conserve the planet’s limited supply of platinum.
The team found that as they decreased the size of the clusters, their catalytic activity for the reduction of oxygen increased. At 12 atoms, each and every atom was exposed at the surface and the catalytic current produced was 13 times that of commercial platinum nanoparticles, which by contrast contain hundreds or even thousands of atoms. According to the researchers, however, the improved performance is probably not due to a simple increase in surface area but to quantum size effects that are not yet fully understood.
They created their sub-nano platinum clusters by adding platinum chloride to dendritic phenylazomethine (DPA) templates – branched molecules that function as rigid, cage-like structures in which the metal atoms became trapped. They were able to tightly control the number of metal coordination sites, and therefore platinum atoms, in each cage. Adding a reducing agent released the platinum clusters as stable structures.
Hoping this would make fuel cells cheaper, we can only wish this technology evolves and comes to the market as soon as possible, because hydrogen is the cleanest energy carrier on Earth, producing nothing but water after its usage. Storage solutions also have a parallel evolution, and it seems to keep up. But that’s another story.