Method for Supporting Platinum on Single-Walled Carbon Nanotubes for a Selective Hydrogenation Catalyst

We have prepared a novel material, consisting of Pt particles supported on purified single-walled carbon nanotubes (SWNTs), representing the first reported metal-loaded SWNT material. The material contains 10 wt % Pt on entangled SWNT bundles consisting of 20−100 nanotubes each. The average Pt particle size is 1−2 nm. High-resolution transmission electron microscopy (HRTEM) observations combined with electron energy-loss spectroscopy (EELS) indicate chemical bonding between Pt and the SWNT surfaces. This bonding is accomplished presumably by ion exchange on carboxylic acid sites created on the nanotube surfaces by slow wet oxidation in dilute HNO3. In addition, a simple SWNT purification scheme requiring no filtration was developed for the preparation of this material. The purification results in a well-defined structure for the metal support useful for investigating the role of this material as a heterogeneous catalyst and the effects of metal−support interactions (MSI). Preliminary kinetics measurements of the activity of this material for the selective partial hydrogenation of 3-methyl-2-butenal (prenal) to 3-methyl-2-butenol (prenol)a representative reaction important in the fine chemicals industryindicates the desired catalytic selectivity above 75 °C, demonstrating a utility of this material that can be optimized in future work.