Unified theory of metal-oxide interactions for platinum-group three-way catalysts

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K04935
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 29020:Thin film/surface and interfacial physical properties-related
• Research Institution: Osaka University (2019-2021); Kyoto University (2018)
• Principal Investigator: Koga Hiroaki 大阪大学, 理学研究科, 招へい研究員 (80519413)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 表面科学 / 自動車触媒 / 金属・金属酸化物接合 / 貴金属クラスター / NOx還元反応 / 電子状態計算

Outline of Final Research Achievements

Platinum-group metal (PGM) three-way catalysts are widely used for treating exhaust gases from gasoline engines. These catalysts are uniquely heterogeneous systems consisting of PGM clusters and metal oxide particles. To understand their workings, numerous physical and chemical effects such as size effects and metal-support interactions need to be clarified consistently and comprehensively. In the present study, electronic-structure calculations were performed on thirty combinations of five PGMs, two cluster sizes, and three metal oxides. Multi-faceted, multi-dimensional analysis of various physical quantities (cluster charges, NO adsorption energies, and dissociation transition-state energies, etc.) was carried out. Consequently, the Lewis acidity of the metal oxide has been identified as the key factor for the NO reduction activity.

Free Research Field

物質科学

Academic Significance and Societal Importance of the Research Achievements

白金族三元触媒は，貴金属クラスターと金属酸化物粒子という大きく異なる物質を接合したヘテロ接合系として，表面・界面科学の興味深い研究対象である．金属種，クラスターサイズ，担体との接合構造など，様々なパラメータが複雑に関与しており，このような複雑系に対する有効な計算科学アプローチを確立することは，今後の計算科学・物質科学の発展に必要不可欠である．また，白金族三元触媒は今日の自動車社会においては大気汚染防止の要となる物質であり，ここで得られた知見は更なる活性向上と貴金属担持量低減のため極めて重要である．