Nanoparticles are appealing in the use in catalysis, hydrogen and data storage, and nano-scale sensors. Their size imparts them with a high surface-to-volume ratio which corresponds to a higher number of active sites per mass/volume. Additionally, nanoparticles exhibit unusual characteristics that arise from their small size, which allows quantum forces to be on the same scale as longer range forces.
Naturally, the properties of a nanoparticle can be controlled by manipulating its size, shape, and constitutive elements. Since a nanoparticle has a small (if any) bulk phase, the surface atoms cannot be ignored. This will give rise to an inhomogeneous nanoparticle. The size and composition of possible multiple phases may depend on temperature and any heat treatment.
Nanoparticles of known overall composition can be produced, but must be chemically and/or heat treated to remove unwanted residues. This may be the cause of surface enrichment of an element (Ren et al.) This will alter the catalytic (along with other) properties of the nanoparticle. Naturally, it would be of great benefit to be able to relate the initial and final surface compositions with the thermal treatment method.