Preparation of hydrophobic platinum catalysts using a water-in-CO 2 microemulsion

Abstract

The hydrophobic platinum catalyst for the chemical exchange reaction between water and hydrogen was prepared by the two-step reduction of 1,5-cyclooctadiene dimethyl platinum (II): A reduction using the reducing agent of sodium tetraborohydrate solution in a water-in-CO 2 microemulsion and the auto-catalytic reduction using hydrogen gas. The platinum particles were locally dispersed on the nano-textured hydrophobic layer formed on the gauze. Their average size was about 50 nm in diameter using a scanning electron microscope and energy dispersive X-ray spectroscopy. The hydrophobicity of the gauze did not decrease even after the deposition of the platinum nano-particles based on a measurement of the amount of water absorbed on the gauze. The hydrophobic platinum catalyst developed in this study was found to be effective for the isotopic exchange reaction of hydrogen atoms between hydrogen and deuterium even in the presence of water. The hydrogen and deuterium atoms were dissociated and exchanged with each other on the surface of the platinum particles and HD was generated. The HD/D 2 ratio increased from 0.012 to 0.050.