Platinum–hydrogen vibrations and low energy electronic excitations of 13-atom Pt nanoclusters

Abstract

Two

Magnetic Properties and the Superatom Character of 13-Atom Platinum Nanoclusters

“…Unlike the surfaces of bulk Pt crystallites which can bind a single H atom per surface Pt, the Pt13 clusters can bind up to 38 ± 2 hydrogen atoms [35], i.e., 3 H atoms per Pt, mostly by over-edge bonding of H to two Pt atoms, as confirmed by FTIR spectroscopy [36]. The bond ionicity depends critically on the ionization potential of the two bonding partners, 13.6 eV for H and 9.0 eV for atomic Pt, leading to clear hydridic bonds.…”

Fine Dispersion of Pt4–5 Subnanoclusters and Pt Single Atoms over Porous Carbon Supports and Their Structural Analyses with X-ray Absorption Spectroscopy

“…One is the multiple adsorption of hydrogen atoms on the surface of each Pt atom, i.e., the formation of hydrogen-rich species. For example, many researchers have reported the hydrogen chemisorption of Pt subnanoclusters supported on oxide materials with a H/Pt ratio of more than 1.0 and experimentally demonstrated the formation of such hydrogen-rich Pt species. − Another possibility is the hydrogen spillover. There are many studies on enhanced hydrogenation catalysis and hydrogen storage based on a hydrogen spillover mechanism induced by Pt nanoparticles on carbon supports. − We have also found enhanced hydrogen storage in the range of 0–80 °C when Pt nanoparticles (mostly less than 4 nm in diameter) are loaded on ZTC and ascribed it to the hydrogen spillover .…”

Weakly-bound hydrogen on defected Pt(111)

“…4). Bridged H adsorption at step sites tilted toward the descending step, which would reduce the repulsion from the nearest H atoms adsorbed the upper terrace, has been suggested [68]. The unoccupied FCC threefold sites within the rectangle would be less active sites for dissociative H 2 adsorption due to the highly coordinated inner-corner Pt atom (labeled '2' in the drawing) and the very short distance from the H atoms adsorbed at the upper step edge [62].…”

“…Thus, our roughened surface with a defect density of~12% would have approximately 8-atom wide terraces separated by (111)-or (100)-type steps on average. Since the local step coverages at the saturation of H and CO are not expected to exceed those on the (111) terrace, i.e.,~1 H [10,15,16,25,28,49,68] and~0.5 CO [3,[51][52][53][54][55][56][57][58][59][60][61][62]69,70] per platinum atom, respectively, the total H and CO uptakes would not increase significantly if all H atoms and CO molecules adsorb on the topmost surface sites only. In spite of this consideration, the saturation H and CO uptakes by the defected Pt(111) surface are larger by~1.48 and~1.1 times, respectively, those on the smooth surface (see the data in Figs.…”