Water Formation on Clean and Vanadium Oxide Covered Pd(111) by Permeating Deuterium

Abstract

In this work the formation of D2O on vanadium oxide (VOx) thin film nano structures on Pd(111) has been investigated. Quadrupole mass spectrometry has been used to determine the flux of the reaction products desorbing from the surface. In separate experiments low-energy electron diffraction and Auger electron spectroscopy were applied to monitor possible changes in the surface composition under reaction conditions. The experiments were carried out at sample temperatures of 523 and 700 K. The water reaction was fed with atomic deuterium via bulk permeation and simultaneous dosing of molecular oxygen. It turned out that the VOx coverage as well as the sample temperature have significant influence on the reaction. The D2O formation rate drops with increasing VOx coverage and increases with rising sample temperature. Additionally, we found evidence that the VOx structures change during water formation, especially at 700 K.