Pd-H interaction of monodispersed Pd, Pd-Ag and Pd-Cu nanoparticles

The idea behind this book is to combine the size dependent and alloying induced modi¿cations in the hydrogenation properties to achieve improved Pd-H interaction. To tailormade the size selected Pd, Pd-Ag and Pd-Cu nanoparticles, Gas Phase Synthesis technique is used because of its better size control over other techniques. The morphological, structural and electronic properties of the above nanoparticles were studied using XRD, TEM and XPS. TEM confirms the monodisperse and crystalline nature of the nanoparticles. XPS shows that the core level and valance band binding energies increase on decreasing the size of the nanoparticles which is consistent with the observed lattice contraction on decreasing the size as revealed by XRD studies. In-situ XRD in the presence of hydrogen predicted more hydrogen absorption in smaller nanoparticles. Elastic recoil detection analysis (ERDA) measurements on Pd, Pd-Ag and Pd-Cu nanoparticles, confirmed the increased incorporation of hydrogen in nanoparticles of smaller size. The increased hydrogen incorporation at smaller sizes has been attributed to the observed shift in XPS valance band binding energy away from the Fermi edge.