Platinum Metals Rev., 2002, 46, (3), 105
3D Platinum Nanoparticle Networks
Assembling nanosized metal particles from their basic components, such as colloids or molecules, into ordered arrays is believed to offer ways of creating new nanostructured materials with properties different to the bulk material. For instance, adding a few hundred atoms or less to electronic or optical devices, allows a single particle to show quantum size effects. A number of nanocrystal superlattices and colloidal networks have already been produced, but the ‘bottom-up’ preparation of nanoparticles to give three-dimensional (3D) structures remains a challenge.
Now a team in Germany have produced nanostructured metal/organic networks by cross-linking Al-organic-stabilised Pt nanoparticles with bifunc-tional organic spacer molecules (H. Bönnemann, N. Waldöfner, H.-G. Haubold and T. Vad, Chem. Mater., 2002, 14, (3), 1115-1120). Pt particles were formed by reacting Pt(II) acetylacetonate with Al(CH3)3 at 60°C in Ar, forming an air-sensitive Pt colloid with a Pt:Al ratio of ∼ 1:2. The Pt is thought to be surrounded by a highly reactive protective Shell which allows protonolytic chemical reactions to occur. The colloidal particles can be cross-linked by bifunctional alcohols. Incorporating spacer molecules increases the interparticle distance. This method may thus form the basis for preparing highly ordered networks.