Proton reduction at surface of transition metal nanocatalysts

Catalytic activities of neutral and charged palladium (Pd) nanoparticles are compared for hydrogen reduction half-reaction. In this work the sequential H₂ dissociation from the surface of a Pd₁₃H₂₄ cluster is systematically studied by ab initio molecular dynamics (AIMD) at the density functional theory level. AIMD simulation is launched by preparing initial values of momenta of all nuclei in the model corresponding to a temperature range of 0–1700 K. AIMD simulation provides the trajectories of all the atoms in the cluster. A sequential H₂ desorption up to seven molecules is observed from the cluster surface due to thermal motion of nuclei. Modifications of total charge on the neutral Pd₁₃H₂₄ cluster model are found to affect surface H₂ desorption behaviour. A desorption rate of H₂ molecule on both neutral and charged Pd₁₃H₂₄ clusters is compared to the data of Pt₁₃H₂₄ cluster reported previously. The H₂ desorption energy on all the investigated clusters is also determined. The results reveal that Pd₁₃ cluster presents a higher catalytic activity than Pt₁₃ cluster.