Iron rusts. Silver tarnishes. Such low-energy transformations of metals are among the most obvious and ubiquitous examples of surface chemistry. Yet currently, "no one can predict what [chemical] reactions will occur on a pure metal surface," notes Eric W. McFarland of the University of California, Santa Barbara. Consequently, all solid metal-based catalysts have been found empirically rather than designed from scratch.
New experiments by McFarland and his colleagues in California and Germany are clarifying what happens when an atom or molecule settles onto a metallic surface, even briefly, and then reacts with the metal. Such adsorption reactions (SN: 12/10/94, p. 390) play a vital role in industrial processes that use metal catalysts to create many important chemicals.