Nuclear Dynamics and Electronic Effects of Hydrogen on Solid Surfaces

Abstract

Hydrogen is involved in a variety of chemical processes on surfaces. While hydrogen exhibits vibrational and rotational dynamics in its adsorption state, it in some cases undergoes diffusion into the substrate as well as on the surface, and participates in chemical reactions. Furthermore, hydrogen exchanges an electron with surfaces having a significant effect on the surface electronic structure. In this personal account, we review our recent studies on surface nuclear dynamics of hydrogen, hydrogen transport across surfaces, catalytic hydrogenation/isotope exchange reactions, and charge transfer between the surface and hydrogen by using a depth-resolved technique of nuclear reaction analysis and a quantum-state-selective detection of resonance enhanced multiphoton ionization in combination with surface science techniques. As a future prospect, we refer to ultraslow μ spin rotation spectroscopy for a direct probe of the hydrogen charge state at surfaces.

Toward an Understanding of Selective Alkyne Hydrogenation on Ceria: On the Impact of O Vacancies on H2 Interaction with CeO2(111)

“…NRA via the resonant 1 H­( 15 N,αγ) 12 C nuclear reaction ( 15 N + 1 H → 12 C + α + γ) was used to analyze the H depth distribution in the H 2 -exposed thin ceria films, using monochromatized 15 N 2+ ion beams of 20–40 nA near the narrow (1.8 keV) reaction resonance energy, E R = 6.385 MeV. The method is described in detail elsewhere. ,− Briefly, the γ-ray yield emitted in the nuclear reaction normalized to the number of incident 15 N ions quantitatively determines the density of 1 H nuclei in the sample. The 15 N ion current is measured with a Faraday cup on the beamline and the γ-detection efficiency was calibrated with Kapton ((C 22 H 10 O 5 N 2 ) n ) foil as a H concentration standard.…”

A Heterothermic Kinetic Model of Hydrogen Absorption in Metals with Subsurface Transport

“…Research into the adsorption and desorption of hydrogen at metal surfaces has made significant progress, and the corresponding physical mechanisms for these processes have been established [7][8][9][10][11]. However, the behavior of hydrogen at the subsurface sites is still poorly understood [12]. Moreover, the atomic-level hydrogen absorption mechanism has not been established yet, and scientists have been debating between the penetration mechanisms, quantum tunneling, or a multi-atomic concerted process [12].…”

“…However, the behavior of hydrogen at the subsurface sites is still poorly understood [12]. Moreover, the atomic-level hydrogen absorption mechanism has not been established yet, and scientists have been debating between the penetration mechanisms, quantum tunneling, or a multi-atomic concerted process [12].…”

“…For metals featuring high surface activity for the dissociative adsorption of hydrogen molecules, such as Pd [12][13][14][15], the transport of hydrogen across the subsurface region often becomes the rate-determining process, in contrast to metals featuring lower surface activity, such as Mg [16][17][18].…”

Effect of Hydrogen-Induced Metallization on Chemisorption

“…It has been found both experimentally and computationally that hydrogen adsorption can induce surface metallization of insulators and semiconductors. , This has been first shown for SiC and ZnO . Then, in 2009, Duan and workers predicted that hydrogen adsorption could induce surface metallicity on SrTiO 3 (001) from the first-principles density functional theory (DFT), which was subsequently confirmed experimentally by D’angelo et al , This phenomenon has also been found later on BaTiO 3 .…”