Building blocks of nanosized supported metals for catalysis: Carbonyl clusters or colloids?

As case studies, two methods on the preparation of supported metal nanoparticles for catalytic purposes are discussed: (i) starting from metal carbonyl clusters and (ii) growing particles in liquid phase followed by deposition on support or in situ fabricating them on the support in solid/liquid interfacial layer. We highlight the advantages and disadvantages of the different techniques with special regard to the size control and stability of the catalysts obtained.