Pt nanoparticle array model catalysts with 28 ( 2 nm diameters and 100 ( 2 nm interparticle spacing have been fabricated with electron beam lithography on alumina supports. A novel method for cleaning the Pt nanoparticle arrays, involving low dosages of NO 2 and CO and mild temperature flashing, was established. This cleaning procedure was crucial for measuring reaction rates over the nanoparticle arrays. The reactivity of the Pt/Al 2 O 3 arrays was compared to a Pt(111) single crystal for the ethylene hydrogenation reaction. The activation energy and the pressure dependence of the H 2 and C 2 H 4 on the nanoparticle array were in excellent agreement with the kinetic data on the Pt(111) single-crystal model catalyst. Because the ethylene hydrogenation reaction is structure insensitive, the rate equation for Pt(111) can be applied to the Pt nanoparticle arrays. The calculated turnover frequency led to a calculated active metal surface area that compared very well with an active metal surface area on the basis of geometry. This reaction can therefore be used to determine the active metal surface area of the Pt nanoparticle array model catalysts. The arrays were characterized with AFM, SEM, XPS, and AES before and after being exposed to reaction conditions.

A photolithography-based method capable of size reduction to produce sub-10-nm Si nanowire arrays on a wafer scale is described. By conformally depositing a material (silicon oxide or silicon) that has a different etching property over a lithographically defined sacrificial sidewall and selectively removing the sacrificial material, the sidewall material is preserved and can serve as nanopattern mask for further processing. The resolution of this method is not limited by photolithography but by the thickness of the material deposited. The application of size reduction nano-patterning method can range from the fabrication of biosensors to model catalyst systems.

The development of synthetic catalysts is inspired by nature's use of enzymes to achieve high reaction rates and 100% selectivity. These natural catalysts often contain inorganic nanoclusters at the active site, and it is an understanding of the activity and selectivity of these nanoclusters and their interaction with the surrounding protein, which can aid in the design of synthetic catalysts. Since natural and synthetic catalysts are composed of these nanoclusters, the fields of catalysis and nanoscience are inextricably linked.