Development of catalysts for alkane oxidation using polyoxometalates with precisely constructed metal multinuclear structures

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K15085
• 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): 2020-04-01 – 2022-03-31
• Keywords: メタン / ポリオキソメタレート / 酸素酸化 / ホルムアルデヒド / 鉄導入ポリオキソメタレート / 高分散担持触媒

Outline of Final Research Achievements

Direct oxidative conversion of methane into useful C1 products, as an example of oxidation of lower alkanes using oxygen, remains challenging due to the low reactivity of methane and its facile overoxidation into carbon dioxide under high temperature conditions. Desired products such as methanol and formaldehyde are more reactive than methane, making it difficult to control selectivity. Therefore, we developed a new strategy that by synthesizing uniform heterogeneous catalysts with precisely designed metal active sites using metal-introduced polyoxometalates, we could rationally design an active site structure that exhibits high selectivity in the methane oxidation. In this study, we used a diiron-introduced polyoxometalate as a precursor to form thermally stable iron oxide subnanoclusters on SiO2, which selectively converted methane into formaldehyde and carbon monoxide (methane conversion, 2.3%; selectivity, 87% at 873 K after 1 h), maintained its catalytic activity even after 24 h.

Free Research Field

触媒化学

Academic Significance and Societal Importance of the Research Achievements

本研究の目標が実現されれば、多大なエネルギーやコストを消費する合成ガス製造プロセスを経由せず、含酸素化合物を含む有用な化学原料を合成できるようになる。また低温触媒プロセスは高温のそれと比べてプロセス全体の簡便・低コスト化につながり、これまで実現し得なかった新たな需要(オンサイト・オンデマンド合成)を生み出すことが期待される。学術的には、新規な担持金属導入POM触媒の設計や新規触媒系を提供する点で波及効果は大きい。近年、触媒インフォマティクスの発展により計算化学的手法で活性点構造を予想することが可能となってきているため、POMに組み込み固体触媒を創出するなどの発展も期待される。