Surface Properties of Air-Exposed α-Ti–Pd Alloys via XPS and Cross-Coupling Reaction

抄録

To identify the reasons why Ti–Pd alloys for hydrogen storage materials show good hydrogenation properties, X-ray photoelectron spectroscopy and the Suzuki–Miyaura cross-coupling reaction were used to investigate a small amount of Pd added Ti–Pd alloys. Pd in or on Ti oxide films is in a valence state of 0 (Pd⁰). Catalytic activity was shown by Pd⁰ in the Suzuki–Miyaura cross-coupling reaction. Therefore, the enhanced hydrogenation properties of Ti–Pd alloys for hydrogen storage materials is due to Pd⁰’s catalytic activity in dissociating hydrogen molecules. In addition, the potential catalytic activity of Ti–Pd alloys was shown to be based on a Pd catalyst.

XPS and cross-coupling reaction (CCR) were used to investigate the surface property of Pd in Ti-Pd alloys. Pd was present in a valence state of 0. Despite the flack-like shape of the alloy, the cross-coupling reaction proceeded up to 94% in product without pretreatment, such as heating in H₂ atmosphere and in air conditions.