XPS study on the vanadocene-magnesium system to understand the hydrogen sorption reaction mechanism under room temperature

Abstract Magnesium surface dope with vanadium has been considered as one of the best material for the hydrogen storage application. Optimization of vanadium concentration doping is important to retain the hydrogen storage capacity above 6 wt %. Vanadocene, bis(η5-cyclopentadienyl) vanadium, with the formula V(C 5 H 5 ) 2 , commonly abbreviated as Cp 2 V is considered as the best precursor for the vanadium to dope the optimized concentration of vanadium over the Mg surface. The vanadium doping over the magnesium has been studied by X-ray photoelectron spectroscopy (XPS) in details. The vanadium doped Mg has been found to be hydrogenated even at 0 °C under nominal hydrogen pressure (above plateau pressure). Besides, the dehydrogenation temperature was also found to be below 200 °C which is remarkable less as compared to pure magnesium, and comparable to the best catalysts for Mg-MgH 2 system reported till date.