R.J. Westerwaal
30 records found
1
Authored
Using the change in the intrinsic optical properties of YMg-based thin films upon exposure to hydrogen, we observe the presence of hydrogen at concentrations as low as 20 ppm just by a change in color. The eye-visible color change circumvents the use of any electronics in this ...
For many hydrogen related applications it is preferred to use optical hydrogen sensors above electrical systems. Optical sensors reduce the risk of ignition by spark formation and are less sensitive to electrical interference. Currently palladium and palladium alloys are used ...
Mg2NiH4 thin films have been prepared by activated reactive evaporation in a molecular beam epitaxy system equipped with an atomic hydrogen source. The optical reflection spectra and the resistivity of the films are measured in situ during deposition. In ...
The engineering of pure and metal alloy catalysts for hydrogen absorption is needed to improve the kinetics of hydrogen-related devices. We introduce a new route to search for alloys that can yield superior catalytic behavior for hydrogen absorption, using an optical technique ...
Hydrogen absorption by a thin Mg2Ni film capped with Pd results in the nucleation of the Mg2NiH4 phase at the film/substrate interface. On further hydrogenation, a self-organized two-layer system consisting of a Mg2NiH0.3/ ...
A novel optical technique to measure catalytic activity for hydrogen sorption is presented. The catalytic activity of the noble metals of Pd, Ni, Cu and Ag is studied as function of pressure and temperature. The uptake rate is limited by chemisorption as deduced by modelling k ...
Thin films of Mg2NiHx which exhibit a remarkable black state with low reflection over the entire visible spectrum were investigated. The films show zero transmission and a low electrical resistivity. It was shown that such a black state is not explicable ...