P2-574Hydrogen Atom Occupancy Sites on the Topmost Surfaces Analyzed by Low-Energy Ion BeamsHydrogen Ion Materials Group, GREEN Taku SuzukiE-mail：： SUZUKI.Taku@nims.go.jpKey Words: Ion beam analysis, Topmost surfaces, HydrogenDue to its significance in catalysis and photocatalysis, the surface hydrogen on the topmost surfaces of TiO₂-related materials has attracted attention. Our recent discovery that TiO2can selectively sense trace amounts of hydrogen in the air has also motivated surface hydrogen analysis. In this context, identifying the hydrogen occupancy site on hydrogenated TiO₂ surfaces has become increasingly important.⚫Low-energy ERDA is one of the few surface analytical techniques that can potentially determine the position of hydrogen atoms on solid surfaces.⚫However, there is a challenge to achieve the surface hydrogen analysis. It is a peak overlap problem.ConclusionERDA apparatus and principleSurface hydrogen analysis⚫Combining the TOF and energy analyses for detecting the emitted particle from the surface in low-energy ERDA. ⚫Applications to a hydrogenated TiO2-related material surface.Future PlanIntroductionLow-energy elastic recoil detection analysis (low-energy ERDA) is a well-established analytical technique for studying solid surfaces. It is particularly powerful for analyzing light elements, such as hydrogen. Low-energy ERDA is one of the few techniques that can potentially determine the atomic occupancy site of hydrogen on the topmost surface.Theme underDiscussionSchematic of (a) recoil of a H atom and (b) He+ion scattering in low-energy ERDA. There are four particles detected in low-energy ERDA, which are direct recoil (DR), surface recoil (SR), single scattering (SS), and multiple scattering (MS).The relationship of recoil H (red), scattered He+(black), and recoil O (blue) between TOF, energy of the particle emitted from the surface (E1, E2, EMS, or ESR), and the incident energy E0. The scattering and recoil angles are both 37°.(a) Low-energy TOF-ERDA spectrum on a rutile TiO2surface. (b) The calculated relationship of various elements between the energy of the particle emitted from the surface (E1, E2, EMS, or ESR) and TOF. (c) Low-energy EA-ERDA spectrum on a rutile TiO2surface. (d) Expanded view of (b). The incident energy E0is 1500 eV. The scattering and recoil angles are both 37°.
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