Thermal and solvent effects on catalytic reactions over heterogeneous catalysis

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K06563
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Catalyst/Resource chemical process
• Research Institution: Hokkaido University
• Principal Investigator: NAKAYAMA AKIRA 北海道大学, 触媒科学研究所, 准教授 (10422007)
• Research Collaborator: Nisanth Nair N.
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 第一原理計算 / 不均一系触媒 / 第一原理分子動力学法

Outline of Final Research Achievements

We aimed to understand the thermal and solvent effects on catalytic reactions occurring at the liquid/solid-oxide interface. First-principle MD simulations were performed to provide microscopic insights into structures and dynamics at the interface. We primarily focused on reactions over CeO2 and the following two topics were investigated. First one involved the formation of strong base site by unique adsorption of 2-cyanopyridine over CeO2. We identified the adsorption structure and reaction mechanism of hydromethoxylation of acrylonitrile in methanol were elucidated by the first-principle MD simulations. Second topic is related to the reaction mechanism of the direct synthesis of dimethyl carbonate from CO2 and methanol over CeO2. Based on the free energy profiles, we found that intermediate with an oxygen vacancy is formed during the reaction, and the stability of this intermediate is a key factor that makes CeO2 an efficient catalyst for this reaction.

Free Research Field

計算化学

Academic Significance and Societal Importance of the Research Achievements

これまでの不均一触媒反応の理論計算の多くは、実験的に報告（仮定）された各中間種や活性種において、気相中または簡素にモデル化された溶媒（例えば連続体モデル）中での安定構造と遷移状態を求める研究がほとんどであった。本研究の特色は、これまでの静的なポテンシャル曲面の議論だけでは得ることのできなかった動的な反応機構（熱揺らぎやエントロピーの効果）に着目し、不均一系触媒における触媒反応のシンプルな原理抽出を目指し、さらにその揺らぎや溶媒効果を制御した合理的触媒設計への指針を与えるものである。