ABSTRACT
The feature which makes nanoparticles so interesting is the relatively high proportion of surface atoms which the possess. As methods of preparing nanoparticles are still relatively crude, producing assemblages which inevitably show a very broad distribution of particle sizes. For this reason, even the structural information concerning nanoparticles which is becoming available is comparatively crude. One of the most striking examples of the latter behaviour concerns the poisoning of platinum catalysts by sulphur. When used in catalytic applications, platinum is normally dispersed in the form of metal nanoparticles on an inert support such as a-alumina with sizes in the range 1–10 nm. In view of the potential, and so far unknown impact on the environment, both physical and biological, similar progress in the field of inorganic nanoparticles might seem to be advisable. All the nanoparticle structures described so far, although unique to the particles concerned, are basically modifications of structures found in bulk material.
