Quantitative Analysis of Residual Hydrogen on Platinum Surface by Atom Probe

Abstract

The paper reports results of a systematic investigation of electric field effects on residual H signals in atom probe analysis. Three species, H⁺, H₂⁺, and H₃⁺, can be detected on a Pt surface without gas introduction into the ultra-high vacuum chamber. The H⁺ ions are more likely to be detected at a higher electric field. On the other hand, the H₂⁺ and H₃⁺ ions appear at the lower electric field. A comparison of residual H and a D₂ gas confirmed that residual H is in the H₂ gas form. H₂ can be dissociated to H on the Pt surface. Consequently, H, H₂, and H₃ coexist on the Pt surface and desorb at an appropriate electric field.