Fabrication of Dense Arrays of Platinum Nanowires on Silica, Alumina, Zirconia and Ceria Surfaces as 2-D Model Catalysts

Abstract

High-density arrays of platinum nanowires with dimensions 20 nm × 5 nm × 12 μm (width × height × length) have been produced on planar oxide thin films of silica, alumina, zirconia, and ceria. In this multi-step fabrication process, sub-20 nm single crystalline silicon nanowires were fabricated by size reduction lithography. The Si nanowire patterns were then replicated to produce a high density of Pt nanowires by nanoimprint lithography. The width and height of the Pt nanowires are uniform and are controlled with nanometer precision. The Pt surface area is larger than 2 cm2 on a 5 × 5 cm2 oxide substrate. The catalytic oxidation of CO was carried out on zirconia-supported Pt nanowires. The reaction conditions (100 Torr O2, 40 Torr CO, 513–593 K) and vacuum annealing (1023 K) did not change the nanowire structures.