Control of electronic structure of μ-oxo based on polyoxometalates and its application to selective oxidation reactions

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K14539
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 27030:Catalyst and resource chemical process-related
• Research Institution: The University of Tokyo
• Principal Investigator: Yabe Tomohiro 東京大学, 大学院工学系研究科(工学部), 助教 (40803234)
• Project Period (FY): 2022-04-01 – 2024-03-31
• Keywords: メタン / 選択酸化 / ポリオキソメタレート / サブナノクラスター / 酸化鉄

Outline of Final Research Achievements

In this study, multiple μ-oxo structures were designed using lacunary polyoxometalates as molecular templates to create metal multinuclear active sites. By controlling the reactivity of the bridging oxygen, selective oxidation of methane by oxygen was achieved. Iron-containing polyoxometalate catalysts, specifically those with fewer nuclei, were designed to have the targeted μ-oxo structures by controlling at the atomic level and were highly dispersed on oxides. It was found that this method resulted in the formation of highly dispersed Fe-μ-oxo structures. In these highly dispersed Fe-μ-oxo structures, the reaction mechanism supposed to involve the direct activation of oxygen, rather than the Mars-van Krevelen mechanism, which primarily proceeds through lattice oxygen in bulk oxides. This strategy establishes one approach for controlling the reactivity of bridging oxygen.

Free Research Field

触媒化学

Academic Significance and Societal Importance of the Research Achievements

本研究では、1原子単位で構造を制御して狙ったμ-オキソ構造を有する金属多核活性点を設計したポリオキソメタレート触媒を酸化物に高分散に担持することによって、非常に高分散なFe-μ-oxo構造の形成やメタン選択酸化における触媒特性を調べた。前駆体であるポリオキソメタレート中の鉄の核数が小さいほど目的の架橋酸素が効率よく形成することを見出し、メタン選択酸化活性が髙い架橋酸素を豊富に有する触媒設計指針が得られた。メタン酸化は生成物の反応性が原料よりも高いために反応の制御が難しく工業化が難しい。本触媒系はこの問題点を解決する一助になると考えられるため、社会的に意義深い成果が得られた。