Hydrogen Interaction with Tungsten Disulfide Nanostructures

Abstract

We report here on hydrogenation of inorganic nanostructures of WS2 by various hydrogenation methods. Our methodology of hydrogen activation by cold plasma, either microwave or radiofrequency, resulted in substantial increase of the hydrogen adsorption rate. We elucidate the chemical state of so adsorbed/absorbed hydrogen by both experimental methods and using theoretical modelling with density functional theory (DFT). The experimental results revealed that hydrogen is mostly physisorbed it also confirmed its stability at the room temperature conditions along with relative simplicity of controlled release by moderate heating. The DFT calculations were in excellent agreement with the experiment showing the physisorbed state is energetically favorable in the case of surface adsorption in one or several layers. The DFT predicted some increase of the interlayer distance with no adverse influence on the energy balance. This phenomenon opens a new gate to implant foreign species inside the nanoparticles. The preliminary experimental results of Ga implantation following hydrogenation are excellent agreement with these DFT predictions.