Why silver speeds photocatalysis

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A supplement providing a snapshot of the latest developments across the chemical

sciences.

Why silver speeds photocatalysis

The mystery surrounding why silver deposits on the surface of titanium dioxide

(titania) make the material a better photocatalyst for breaking down some

organic molecules but not others might have been cleared up.

Rose Amal and colleagues from the University of New South Wales, Australia, have

explained how the silver removes electrons from titania, making the electrons

and holes created by UV light less likely to recombine. This increases the

number of holes in the material. Because holes catalyse the breakdown of some

organic molecules at the surface, this increases the efficiency of catalysis for

those molecules.

Other molecules are broken down by hydroxyl radicals on the surface of the

material, and for these molecules the silver has little effect.

Photocatalysis is a promising technology for removing organic matter from air

and water and

the authors hope their work will have practical implications in this field.

Madelaine Chapman

References

H Tran et al, Photochem. Photobiol. Sci., 2005, 4, 565 (DOI:

10.1039/b506320e<http://xlink.rsc.org/?DOI=b506320e>)