Abstract
The deposition of Pd nanoparticles on the binary compound Mg0.65Sc0.35 using the Supercritical Fluid Chemical Deposition (SFCD) method was performed. There, the SFCD operating parameters (co-solvent, temperature, CO2 and hydrogen pressure, reaction time) have been optimized to obtain homogeneous deposition of Pd nanoparticles (around 10 nm). The hydrogenation properties of the optimized Pd@Mg0.65Sc0.35 material were determined and compared to those of Mg0.65Sc0.35Pd0.024. The latter compound forms at 300 °C and 1 MPa of H2 a hydride that crystallizes in the fluorite structure, absorbs reversibly 1.5 wt.% hydrogen and exhibits fast kinetics. In contrast, Pd@Mg0.65Sc0.35 compound decomposes into ScH2 and MgH2 during hydrogen absorption under the same conditions. However, reversible sorption reaches 3.3 wt.% of hydrogen while keeping good kinetics. The possible roles of Pd on the hydrogen-induced alloy decomposition are discussed.