Catalytic reaction of peramagnetic oxygen molecule on platinum single crystal surface with perpendicular magnetic anisotropy

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K18801
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Tohoku University
• Principal Investigator: Wadayama Toshimasa 東北大学, 環境科学研究科, 教授 (20184004)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: 酸素還元反応 / 垂直磁気異方性 / 白金コバルト合金 / 白金ニッケル合金 / 表面歪 / スピン触媒

Outline of Final Research Achievements

Pt-skin/Co-underlayer/Pt(111) (Pt-Co(111))and Pt-skin/Ni-underlayer/Pt(111)(Pt-Ni(111))lattice stacking surfaces are prepared in ultra-high-vacuum (UHV) by using molecular beam epitaxy (MBE). While the former Pt-Co(111) surface shows perpendicular magnetic anistropy (PMA), the latter Pt-Ni(111) surface does not show PMA. Commpressive surface strain is induced for both the Pt-skin layers of Pt-Co(Ni)(111) due to underlaid Pt-Co(Ni)(111) lattice layers. ORR activities for both the Pt-Co(111) and Pt-Ni(111) surfaces depend on thermal treatment temperatures in UHV during the sample fabrication process and maximum oxygen reduction reaction (ORR) activity is estimated to be ca. 9-fold higher than clean Pt(111). Nevertheless, dependences of the estimated ORR activities on surface compressive strains of the surface Pt-skin layers for PMA-Pt-Co(111) and non-PMA-Pt-Ni(111) are different, suggesting that PMA of the Pt-skin surface influences the surface reaction of peramagnetic O2 molecules.

Free Research Field

材料界面物性

Academic Significance and Societal Importance of the Research Achievements

本研究は、表面法線方向に揃った磁化が常磁性酸素の表面反応にどのように影響するか実験的に検討し、新たな触媒反応場として提案することを目的として行われた。得られた結果は、Pt単結晶表面における常磁性酸素分子の電気化学的酸素還元反応が垂直磁気異方性(PMA)の付与により影響を受けることを初めて実験的に明らかにしたものであり、「スピン触媒分野」開拓への端緒とすることができたものと考えている。