Direct imaging of catalytic process by differential phase contrast

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K18974
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Materials engineering and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Ishikawa Ryo 東京大学, 大学院工学系研究科(工学部), 特任准教授 (20734156)
• Project Period (FY): 2017-06-30 – 2020-03-31
• Keywords: 微分位相コントラスト法 / グラフェン / 原子電場

Outline of Final Research Achievements

We have successfully observed the atomistic electric fields of single carbon atoms in a monolayer graphene by using our segmented-type detector in the scanning transmission electron microscopy. We have also identified that the atomistic electric fields of single Si dopants in a monolayer graphene is strongly depending on the local symmetry at the located atomic sites. Since dangling bonds are formed at the graphene edge, electric fields are enhanced towards a vacuum that enables to capture cations at the graphene edge. On the basis of our direct observations of atomistic electric fields, we conclude that nano-scale atomistic defects play important roles to enhance the catalytic reactions.

Free Research Field

材料工学

Academic Significance and Societal Importance of the Research Achievements

触媒に代表される化学反応においては，材料中の局所的な原子配列に加え，電場あるいは電子密度分布の空間的な分布を観察する必要がある．平均情報として観察する手法は多く存在しているが，原子スケールでの電場・電荷密度分布を得る手法は確立されていないのが現状である．本研究により，グラフェン中の不純物原子や欠陥構造における電場構造の直接観察が可能となったことから，多岐に渡るナノテクノロジーの分野において様々な応用が期待される．